The Formulation of Premium-Style Ice Milk, Low in Lactose, Sugar and Fat

A low lactose, sucrose-free, fat-free chocolate frozen dessert was developed. This was achieved by combining polydextrose-N as bulking agent, acesulfame-K as sweetener and a microcrystalline cellulose based stabilizer. The product that was developed contained 95 calories per 100 grams. Lactose reduction of 96% was achieved in all milk products that were used when liquid lactase enzyme was added at 3.5% rate. The frozen dessert mix that was developed, when flavored with vanilla or strawberry flavoring agents, gave a product with acceptable body and texture, but unacceptable flavor. As opposed to regular ice cream mixes, viscosity and water activity readings of the mix were not found to be related to the quality of body and texture of the final product, while instron readings indicated some correlation.


INTRODUCTION
Ice cream and ice milk are frozen dairy products made by freezing a formulated mix while agitating in order to introduce air and ensure uniformity and consistency. The exact composition of the mix varies according to the type of product. However, a mix would generally be composed of a combination of dairy products, sweetener (in dry or liquid form) and water; it may also include eggs, flavorings and stabilizer and/or emulsifier, all of wholesome edible material . In the United States, ice cream and ice cream related products are defined by U.S. Government standards (Code of Federal Regulations, 1982).
The first wholesale ice cream industry in the U.S. was established in 1851 in Baltimore, Maryland and by 1920 the value of ice cream as an essential food was generally recognized . Since then, ice cream and all related products have become unusually popular. Annual production of ice cream in the U.S. for 1987 reached 931,398 million gallons, and ice cream related products -frozen milk, ice milk, frozen yogurt etc.-reached 477,469 million gallons (Elliott, 1988; -2-I.I.C. A.,1988). These figures put the U.S. in first place world wide for production of ice cream . surveys which investigate ice cream's popularity, refer to it as the "Great American Dessert". In hotels and restaurants ice cream is served more often than all other desserts available Leeder, 1981).
Ice cream and the food products related to it, are nutritious, palatable, healthful and relatively inexpensive. The energy and nutrient values of ice cream depend directly upon the ingredients from which they are ' made. An average ice cream product will contain milk products, stabilizers, flavoring and other additives like nuts, eggs, fruits etc. Ice cream products are excellent sources of high quality protein. They are good suppliers of calcium, phosphorus, thiamin, riboflavin, vitamin A, vitamin D and other essential nutrients (Bowers and Church, 1985) .
What makes ice cream products so popular, and distinguishes them from all other desserts, is the combination of sweetness and the refreshing effect of the fat as a creamy, rich taste.
Ironically, the factors that make frozen dairy products delicious and widely desirable are also the ones that raise its price and make it unhealthy for some diet conscious consumers (Anonymous, 1989a). These two major components result in -3-the elimination of this food from the diets of millions of Americans that suffer from diabetes and/or obesity N.I.H., 1987).
Another prominent ingredient in ice cream products is lactose, a disaccharide which is the single largest naturally occuring nutrient found in mammalian milk (Crede, 1985). The presence of lactose in dairy products forces close to 60 million Americans with lactose intolerance to exclude such products from their diets in order to avoid the gastrointestinal problems (Skinner and Martems, 1987).
In addition to diabetic, obese and lactose intolerant individuals, other smaller groups of people are also restricted or discouraged from consuming sugar containing products such as ice cream. These include people who suffer from hyperglycemia, hypocholesterolemia, dental plaque and oral diseases (Dahlqvist, 1984;. Consumers are better informed on the subject of diet and health which leads them to look for low fat/low calorie foods (Mermelstein, 1989). Diet conscious consumers -for health or cosmetic reasons -constitute a large and growing portion of the market; "calorie reduction has become an obsession in the 1980's", according to Hendley and Seymour (1988). The "lite" versions of frozen dairy products constitute almost 1/3 of the total frozen dairy -4-production for the last twenty years (U.S.D. A., 1987; r.r.c. A., 1988).
To satisfy this market, the dairy industry has introduced a variety of new products. These products are artificially sweetened, sucrose-free ice milk, frozen yogurt, sherbet, water ices, etc. There are products low in fat and some calories for obese people, products without sucrose for diabetics, or products low in lactose for the lactose intolerant consumers.
careful review of the consumption figures for frozen dairy products during the last ten years (U.S.D.A., 1987; I.I.C. A., 1988), reveals that the only significant increase has occurred with frozen yogurt ( 600% increase ), while products like ice milk or sherbets, remained at constant levels. Only mallorine-type products showed significant decrease in consumption (80% decrease) (I.LC. A., 1988).
All products mentioned above constitute the market which attempts to appeal to the diet/calorie conscious consumer. The basic difference between the three is that flavor and texture of frozen yogurt comes closer to that of ice cream, while it is significantly lower in fat and some calories. On the other hand, ice milk has more fat but less calories than frozen yogurt. Finally, the -5-sherbets lack the thick rich taste of ice cream, but have no fat and less colories than the other two products.
Reviewing the above information demonstrates that among h ice cream related products, only froz. en yogurt, which t e .
has flavor and texture close to that of ice cream, has shown significant increase in consumption figures. This indicates that co~sumers will not easily accept a product that deviates considerably from ice cream in taste and texture.
Products that are out in the market though, do not combine all three desirable characteristics into one product -low lactose, low fat and sugar free. These trends are indicative that the market would be receptive to frozen dairy products significantly lower in calories, fat and lactose than ice cream, but still taste "like the real thing".
The purpose of this study is to develop a product that will have body, texture and taste as close as possible to that of ice cream, while being sucrose-free, low in fat and low in lactose. For this, a combination of new products and current food technology will be used.
New sweeteners, stabilizers, flavors and bulking agents will be tried in various formulations in order to develop an "ice cream-like" product which could serve as a safe alternative for those individuals who must or want to maintain certain diet regimens. -6-

MATERIALS.
Homogenized/pasteurized milk was used throughout this study. Milk was donated by East Greenwich Dairy, Cranston, RI. This is a two stage machine, which can process up to 10 liters of mix at pressures as high as 11,000 psi. were added to the milk, and the mix was then blended until all ingredients were dissolved. A Waring blender ' was used along with a rheostat in order to achieve the desired vortex without any foaming of the mix.
The mix was then batch pasteurized at 69°C -71°C for 30 min.
Immediately after pasteurization, the mix was homogenized at 500 / 2500 psi.
Following homogenization, the flavor was added, and the mix was then cooled in a walk-in refrigerator at 1·c -3·c.
When the mix reached 4°C -5°C, it was transfered to the ice cream freezer. Freezing was conducted until the product reached a temperature between -5°C and -7°C, and an overrun of 55%.
The overrun was calculated by weight (Arbuckle, 1'986), using the following formula: -11-overrun % = mix weight of 1 gal -weight of 1 gal of product weight of 1 gal of product When drawn from the freezer, the product was packed in one-pint plastic containers, covered and allowed to ' harden at -23°C overnight. For this process, samples were placed very close and against the fans of the freezer blowers, in order to minimize the time required for hardening. c. Lactose Hydrolysis: Whole milk, skim milk, cream and dry skim milk were formulated and mixed together for treatment with lactase enzyme prior to the preparation of the ice cream mix. Maxilact L 2000 liquid lactase was added at 3.5% (w/v), and the milk base was allowed to hydrolyze at 1·c -3•c for 24 hr.
The percent of lactose hydrolyzed in each mix was determined by the amount of glucose produced due to the hydrolysis (De Angelis, 1979). Glucose content of the mix was determined before and after lactose hydrolysis with -U-the YSI Glucose Analyzer in mg%. The difference gave the P roduced, indicating the amount of lactose qlucose hydrolyzed.
The percent of lactose content in each formulation was datermined based on the proportional contribution of the following lactose concentrations : Whole milk 4.6% lactose, skim milk 4.9%, heavy cream 2.9% and dry skim milk 50% (Walstra and Jenness, 1984).
The formula for calculating the percentage of lactose hydrolyzed in milk was as follows: ' % lactose hydrolysis= moles of glucose generated due to hydrolysis - moles of lactose in mix before hydrolysis D. Sensory Evaluation and Analysis: One day prior to each sensory test, products were tempered in a freezer at -1s·c. Two-ounce disposable cups were labeled with the code number of each formula tested. One scoop of each sample was placed in each cup. An average of 15 -20 panelists were asked to look, taste and score the samples. Samples were given to the panelists in a random -13-and they were asked to rate these using the score order, card shown in Appendix A. The quality factors examined were those of flavor, body and texture, color, sweetness and melting. For melting qualities, one scoop of each sample was placed in a plate and allowed to melt at room temperature. A size 24 (18/8) scoop was used (Wittinger and smith, 1986; with a saturated solution of sodium chloride      -19-to form when a higher percentage of MSNF was used (Hendley et al., 1988).
2 . sucrose reduction. The sweetness of acesulfame-K haS been reported as approximately 200 times that of sucrose (Anonymous 1986a;Anonymous 1986b). The exact level of sweetness, though, depends on the other ingredients present in the formula, and the way it was processed. In order to establish the correct level of acesulfame-K needed for the substitution of sucrose, five levels of the artificial sweetener were examined as shown in Table 3A. Statistical analysis of the ·sensory evaluation results clearly indicated that formula 1920 (with 0.06% acesulfame-K) was preferred. Levels of 0.04 and 0.05% acesulfame-K were criticized as slightly undersweet and lacking in flavor; levels of 0.08 and 0.1% acesulfame-K, were thought to be too sweet. The fat level was kept at the 16% level. Note that in order to keep the total solids at the same level, more MSNF was used.
All formulations for sucrose reduction received low scores for body and texture (Table 3A), and for melting.
The body of these products was weak and the texture icy and slightly coarse due to the lack of sucrose, which was eliminated from the formulas. Sucrose contributes not only sweetness and bulk to the product, but also absorbs water, and thus reduces water -20-    -24-fat, MSNF, and polydextrose-N. Since fat (which also affects flavor), was being reduced, polydextrose-N and acesulfame-K levels were slightly increased in order to compensate for loss in body and texture and flavor. The results showed that formula 123, containing 3% fat received significantly lower scores than formulas 321 and 23 1 in all four characteristics scored. An off-flavor, followed by an unacceptable after-taste was found in formula 123. since the lowest acceptable fat level appeared to be between 5.2% of formula 321 and 3.1% of formula 123, two more formulations were prepared, as shown in Table 6A.
Formula 884, containing 4.5% fat, and formula 606, containing 0% fat, were tested in order to examine and compare the effects of optimum and complete fat elimination from the formulation. Formula 884 received higher scores for flavor, body and texture and ~el ting than formula 123. The color of the product was still within acceptable levels, although compared to the standard product, it was noticeably darker. This was believed to be due mostly to the lack of fat, the prevalance of polydextrose-N, which contributed a yellowish tinge, and the higher percentage of MSNF.
Comparison of the sensory scores for formulas 123, -25- with 3 % fat, and 606, with 0% fat, shows that the flavor and total scores were very close. Both formulas had a weak body as well as an icy texture. Also, an intense off-flavor followed by an unacceptable after-taste was present in the product.
since no additional defects were detected at the 0% fat level, a decision was made, to investigate the potential to improve the fat-free product.
5. Texture improvement. Both literature , and local industry people suggested incorporation of live culture into the formula in order to improve the texture and flavor. These suggestions were rejected as this research was not focused on "frozen yogurt" type of products.
The need for different types of stabilizers and/or emulsifiers was realized at this point. Various formulations were tried in an effort to correct the defects in body and texture of the fat-free formulations.
Using formula 606, containing 0% fat as a basis, various emulsifiers and stabilizers were tested. Formulations developed were judged for body and texture. Also, the penetration force was measured for a more objective evaluation.
Emulsifiers "Ice #2" and "Dur-Lo" and stabilizer "Sherex 302" were used at levels suggested by the -27-fa cturers. As shown in Table 7, neither of the two manu em ulsifiers contributed any improvements, when new compared to the carrageenan-based Seakem IC 912. The body/texture scores were about the same fo~ all three products, with only slight improvement in the value of penetration force. Stabilizer "Sherex 302" gave a comparatively better body, close to a perfect score of 5, but was too hard and dense, as indicated by a doubling of the penetration force value.
The recommended levels of Sherex 302 for low or non fat frozen desserts were between 0.72 and 0.80% (Microlife Inc., 1989). These levels were too high for this formulation, and resulted in an improved but excessively hard body. Lower percentages of Sherex 302 were tested (Table 8), by both sensory and penetration values. It was clear that a reduction in stabilizer decreased the penetration values, which were all higher than the standard ice cream (Table 7). However, a decrease in Sherex 302 did improve the body and texture significantly at the 0.45% level. This led to the basic formula 697 (Table 9).
Egg yolk solids were not included in this formula. This was done, not only to reduce the cholesterol level of the product, but also because the emulsifying effects of the egg yolk solids were replaced  -31-bY the emulsifiers included in Sherex 302.
The contribution of emulsifiers to the body and texture of a .fat-free product was not clear. Arbuckle ( 1986 ) and Fennema (1985) mentioned that some stabilizers work better in the presence of certain emulsifiers, which may be the reason for the effects found in this study.
since formula 697 was accepted as the one with a body and texture compatible to the standard formula 401, both were compared by sensory evaluation (  -34-.. 2. water Activity. Mixes were tested for water activity (aw) after homogenization and after cooling to room temperature. As shown in Table 13, there was no clear indication from water activity values for the ' potential body and texture of the mixes. Although water activity readings of some mixes were quite close, deviating by only 1.2% (from 91.7 to 92.9% ), the actual body and texture of the final products varied considerably, ranging from too hard to soft and coarse.
Thus, water activity values of the mixes were not proven to be an accurate method of assesing body and texture of the final products.

Instron.
In order to objectively evaluate the body and texture of the finished products, the penetration force was measured by using as Instron 1122 model, equiped with a "round head" probe. This proved to be a useful method for assessing the hardness of Products. Penetration force readings, listed in Table   141 demonstrate higher readings for the experimental -37-  -39-formulas (801 and 697 ), which indicates that at the same t r e the products were harder. This was tempera u beneficial, since the products were not found to be too hard. When soft enough to eat, the experimental products would be at a lower temperature, compared to standard commercial ice cream, and thus would have a more intense sweetness and flavor. Also, the fact that there were no fluctuations on the Instron printouts, indicates that the products were evenly packed, and body was consistent throughout the 4 centimeters of penetration.

CONCLUSIONS.
The following conclusions can be made as a result of this thesis research project.
1. Lactose levels were reduced by 96%, in 24 hrs. at 3\C, in ice cream mix, when treated with Maxilact L-2000 liquid lactase enzyme added at a 3.5% concentration.
2. When low-lactose milk products (whole milk, skim •ilk, cream), were used as ingredients in standard plain vanilla ice cream, sucrose content could be reduced from -40-4 to 11.0% of the mix. This represented a 17.9% 13· reduction. This produced an acceptable low-lactose ice cream product.
3 • When acesulfame-K (Sunette), was used as a substitute sugar in low-lactose ice cream mix, a concentration of 0.06% provided sweetness comparable to ll% sucrose and an acceptable ice cream product.
4. When sucrose was completely substituted with acesulfame-K in a plain vanilla low-lactose ice cream formula, poor body and texture characteristics resulted. s. Polydextrose-N, when added at a level of 18.0%, was found to restore the otherwise unacceptable body and texture in a low-lactose, sugar-free, acesulfame-K sweetened ice cream product. 6. Polydextrose-N and a carrageenan stabilizer were not sufficient to produce an acceptable body and texture in a low-lactose, sugar-free, acesulfame-K sweetened and fat-free frozen dessert.

The microcrystalline cellulose based stabilizer
Sherex 302, at a 0.45% level, in conjunction with 24% polydextrose-N, gave an acceptable body and texture to the low-lactose, sugar-free, · fat-free frozen dessert. An -47-

APPENDIX "A"
Sensory Evaluation Scoring Card. -48- Polydextrose (see Figure 1) -a patented food ingredient developed by Pfizer Research -is a water-soluble, randomly bonded condensation polymer of dextrose, containing minor amounts of bound sorbitol and citric acid (Pfizer Inc,1985). It is prepared by thermal polymerization of glucose in the presence of an acid that functions as a catalyst and a relatively small amount of polyol that functions as a plasticizer (Torces et.al., 1981) • The project that resulted in the development of Polydextrose began in the middle sixties, when due to the general acceptance of the synthetic sweeteners there was a need for a replacement bulking agent (Anonymous, 1984). The objective was a low calorie product with high water solubility and little or no color or flavor, which could Provide the bulk and mouthfeel of sugar without sweeteness -50- (Allingam, 1982 Inc,1985;Dartey et al., 1987, Murray, 1988, and iii) Type-K polydextrose, a dry blend, formulated with potassium bicarbonate so as to provide the same pH (2.5 to 3.5) as polydextrose-N solution when dissolved in water (Murray, 1988). Aqueous solutions can be easily prepared from the powder forms; viscosity of such solutions is somewhat greater than that of sucrose solutions of equal concentrations (Smiles, 1982). -52-that is primarily responsible for the resistance of the to enzymatic attack (Beereboom, 1979). Enzymes find polymer it difficult to hydrolyze carbohydrate molecules of such complexity (Allinghem, 1982) . Polydextrose is partially fermented by fecal microorganisms which produce some volatile fatty acids (VFA) (Allingham, 1982). The VFA are absorbed and calorically used by the host. In man, the caloric utilization of polydextrose is one calorie per gram (Pfizer Inc, 1985;Murray, 1988), or 25 percent that of sugar and 11 percent that of fat. This low caloric • utilization is what allows polydextrose to signif icantlly reduce the caloric density of foods.
All three types of polydextrose were tested and found stable over a 90-day investigative period at temperatures up to 60°C. The only significant change was detected at elevated temperatures where polydextrose-N showed a darkening in color (Murray, 1988).
Polydextrose is amorphous and melts above 130°C. When polydextrose cools down it produces a clear glass, similar to hard confectionery. Unlike sugar, polydextrose will not crystallize (Murray, 1988).
Polydextrose acts as both bulking and bodying agent. As bulking agent, it contributes solids to maintain palatability and textural properties. As bodying agent, it improves mouthfeel and viscosity qualities (Murray, 1988).
-53-polydextrose has been proven safe to humans by many toxicological studies performed in both animals and humans. studies showed that nothing indicates any hazard to These h ealth under the intended conditions of . use for bwnan polydextrose (Torces et al., 1981;Beereboom, 1979). Tests on rrype II diebetics have shown that polydextrose does not siqnif icantly affect blood glucose or insulin ievels (Murray, 1988). Consequently, this product can contribute to the new dietary recomendations of low fat and sugar intakes, by being used as a sugar and/or fat substitute in food formulations (Murray, 1988). Also, other tests have indicated that neutralized polydextrose does not promote tooth decay (Murray, 1988). If large quantities of polydextrose are consumed, laxative effects will result due to fermentative action by the microbial metabolites produced in the lower intestine (Torces et al., 1981, Murray, 1988. Clinical studies resulted in a mean laxative threshold dosage of 90g/day (Beereboom, 1979). If a product has more than 15 grams per serving, it must carry the statement "sensitive individuals may experience a laxative effect from excessive consumption of this product" (Mermelstein, 1989). Acesulfame-K was approved for use in dry beverage mixes, instant coffee and tea, table-top sweeteners and as ingredient in chewing gum, puddings, gelatins and dairy product analogs (Anonymous, 1988;FDA, 1988). 6-methyl-1,2,3-oxathiozine-4(3H)-1,2,2-dioxide (Anonymous, 1988;FDA, 1988).

Acesulfame-K is in a white crystalline form and it is
odorless. It is 200 times sweeter than sucrose and has a clean pleasant taste at low levels of use with no unpleasant aftertaste (Medallion Lab, 1986;Murray, 1988).
It can be easily dissolved in water. The solubility of Acesulfame-K is high, even at room temperature and rises -56-sharply with increased temperatures (Murray, 1988;Klis a.J., 1986). A 20% solution can readily be prepared at 0 11 Fig. 2 Structural formula of Acesulfame-K (Anonymous, 1988).
2o•c. Solubility in ethanol is low but easily enhanced with the addition of water (Klis B.J., 1986).
Acesulfame-K exhibits no distinct melting point (degradation typicaly occurs at 225°C, temperatures much higher than those normaly found in foods even during high-temperature processing) (Murray, 1988;Klis B.J., 1986) • Acesulfame-K is not metabolized by the body and is excreted unchanged (Microlife Inc, 1989;Lipinski, 1985).
In human studies using 14 c-marked acesulfame-K, over 99% of the dose was excreted in urine and less than 1% in feeces (Murray, 1988). From farmacocinetic calculations it was concluded that no accumulation of acesulfame-K in the -57-bodY seems possible even after repeted ingestions within short periods (Murray, 1988).
Exceptional stability in the crystalline state is reported for samples stored for about ten .years at ambient temperature. It is not affected by pH values of 3 or higher (Klis B.J., 1986;Lipinski, 1985).
Like other artificial sweeteners, acesulfame-K has come through pharmacological and toxicological tests with a clean slate (Dermot, 1983). It has been tested in more than fifty studies conducted without any negative findings (Murray, 1988;Anonymous, 1988;Dermot, 1983).
Acesulfame-K was fed to diabetic rats for a prolonged period in order to study its influence on a diabetic organism. In this study no negative effects were observed (Murray, 1988) .
The A.D.I. (acceptable daily intake) set by FDA is lSmg/kg of body weight (Anonymous, 1988c). A lower A.D.I. has been commissioned by WHO/FAO at 9mg/kg body weight (Lipinski, 1985).
According to the supplier's information (Hoechst, 1988), there are quite a few commercial products in Europe containing acesulfame-K, whereas in the US there are none listed, basically due to the very recent approval by FDA (Hoechst, 1988 sherex 302 is a stabilizer designed for use in hard serve frozen dairy products like ice cream and ice milk. A usage rate from 0.46 to 0.90% is recommended by the manufacturer (Microlife Inc, 1989). According to the technical information supplied with the product, Sherex 302 gives excellent stabilization to low-fat or non-fat frozen desserts, with heat shock protection and extra creamy mouthfeel (Anonymous,· 1989b).
Sherex 302 is a white, odorless powder, which disperses rapidly. It contains a combination of not only stabilizers but also emulsifiers as shown below in the ingredients list (Anonymous, 1989b) Fennema, 1985).
oiglycerides are more effective in producing dryness and stiffness and increasing the melting time Fennema, 1985). Dextrose, a refined corn sugar, is sufficiently effective in lowering the water activity while being tolerable organoleptically (Fennema, 1985).
Guar gum is a complex carbohydrate used as a stabilizer. It is readily soluble in cold solutions and gives very good results in combination with CMC and carrageenan for products undergoing HTST or continuous pasteurization (Arbuckle, 1986). Sodium carboxymethylcellulose (CMC), is a stabilizer easily dissolved in the mix (Arbuckle, 1986) . Its water binding capacity makes it useful in ice cream and other frozen desserts, in which it retards ice crystal growth (Fennema, 1985). CMC is used in dietetic foods to provide the bulk, body and mouth feel that would normally be contributed by sucrose (Fennema, 1985 Mermelstein, 1989).
obesity is a health risk associated with a number of diseases. It may predispose an individual to hyperlipidemia, hypercholesterolemia, diabetes (Mermelstein, 1989). Hypertention, digestive diseases, heart and cardiovascular diseases and cancer are also directly correlated to obesity (The Surgeon General's Report, 1988;Murray, 1988 Surgeon General's Report, 1988, Mermel·stein, 1989Murray, 1988). All of these studies have shown clearly and undisputedly that the risk of mortality increases significantly for obese people, and concluded that the obese tend to die young (Murray, 1988;The Surgeon General's Report, 1988;Finer, 1988) The etiology of obesity is complex, related to lifestyle, heredity, aquired physical and physiological -62-disabilities, cultural patterns and personality (The surgeon General's Report, 1988;Finer, 1988 ;Mermelstein, 1989 ). Accordingly, treatments for obesity are complicated _ and not unique. The one common objective shared by all treatments is the loss of weight. In order to lose weight, one must decrease caloric intake, increase caloric expediture, or do both (Finer, 1988). It has been proven that weight loss reduces risks in the obese (The Surgeon General's Report, 1988).
The surgeon General's report (1987) clearly states that Americans in general would benefit not only from a lifestyle that includes more physical activity but also from a diet containing fewer calories. It also urges the industry to continue developing low calorie food products.

Diabetes is characterized by metabolic abnormalities of
Which the most evident is hyperglycemia and elevated concentrations of blood glucose (Metcalfe, 1988, The Surgeon General's Report, 1988. It is also characterized by long term complications involving multiple organs, especialy the eyes, kidney, nerves and blood vessels (Arky, -63-1984, Metcalfe, 1988. These complications result from a deficiency of the hormone insulin, or a reduction of the effectiveness of insulin. There are two major forms of diabetes mellitus: Type-I or insulin-dependent, (IDD) and TYPe-II or noninsulin-dependent, (NIDO) (Metcalfe, 1988, The surgeon General's Report, 1988 (Arky, 1984;Metcalfe, 1988). Also, retinopathy, which for the diabetic is a common cause of blindness (Arky, 1984;. In addition to all above complication· s, diabetes is responsible for about 45% -64-of all nontraumatic leg and foot amputations in the U.S.
(The surgeon General's Report, 1988;. primarily, diabetes mellitus is believed to be a qenetic disease. In diabetes the body is unable to regulate the metabolism of food. The genetic pattern has been related to certain antigens which appear to pass on a predisposition to diabetes rather than the disease itself (Arky, 1984;Metcalfe, 1988). Development of the disease then seems to be determined by varying environmental as well as genetic factors (Arky, 1984). ' currently, there is no cure for diabetes. Prevention of Type-II diabetes is possible. Estimates suggest that new cases of diabetes could be lowered by half by preventing obesity in adults (The Surgeon General's Report, 1988;Metcalfe, 1988). Successful treatment of the disease is complex and depends on cooperative effords of health professionals as well as the patient. No diabetic patient can be successfully treated without following a diet regiment (Metcalfe, 1988). The individual must know what foods to select. A diet containing 50 -60% of total energy as CHO is now recommended for individuals with diabetes (The Surgeon General's Report, 1988). Also, in order to reduce the risk of heart coronary disease, a diet low in fat, saturated fat, and cholesterol is suggested (Arky, 1984, The Surgeon General's Report, 1988. The majority of -65-those involved in diabetic managment and education feel the case for energy-reduced diets in the managment of diabetics has been proven (Metcalfe, 1988). The practical i~plementation of advice that can achieve energy reduction is what must concern the diabetic, the professional advisers, the food industry and the legislative body (Metcalfe, 1988).
Alternative nutritive sweeteners like fructose or sorbitol may be used without direct impact on diabetics but they do contribute calories. On the other hand, ' non-nutritive sweeteners (aspartame, saccharine, sunette etc.), provide no calories on relation to their sweetness.
The American Diabetes Association's current position is that both nutritive and non-nutritive alternative sweeteners are acceptable in the managment of diabetics (The Surgeon General's Report, 1988).

LACTOSE INTOLERANCE
Chemically, lactose is a disaccharide, consisting of one residue each of o-glucose and D-galactose (Lehninger,1982;Walstra, 1984). Lactose, is the natural sweetener of milk, where it is found in levels of about 5%. (Walstra et al., 1984).
-66-Like other disaccharides, lactose must be hydrolyzed before it can be transported through the intestinal membranes. In order to be utilized by the human body lactose has to be hydrolyzed to its monosaccharite components glucose and galactose (Walstra et al. 1984).
This hydrolysis takes place in the brush border mucosa! cells of the intestine, where the enzyme A-galactosidase (lactase) is found (Walstra, 1984;Houts, 1988).
In lactose intolerant individuals this enzyme is present in low concentrations or it is absent. Lack of the ' enzyme lactase results in lactose passing into the large intestine where it is fermented by bacteria, releasing hydrogen (Scrimshaw et al., 1988 andHouts, 1988). Also, lactose present in the large intestine holds water which would otherwise be drawn out osmotically. Thus, digestive-track distress,abnormal cramps, bloating, flatulance and/or diarrhea may result (Walstra et al., 1984) .
Generally, literature suggests that 30 -95% of the lactose intolerant individuals experience the symptoms following ingestions of about 15 to 50 gm of lactose (Walstra et al., 1984;Scrimshaw et al., 1988).
Population groups with low percentage of lactose intolerance (O -30%) are generally found in geographic areas where people are known to have the longest tradition -67 .-of dairying, these areas being North-West Europe, and some pockets of the Mediterranean and Near East countries, Africa and the Indian subcontinent (Houts, 1988). On the other hand, population groups displaying high proportions of lactose intolerance (60-100%) are found in areas where dairying or adult milk usage has never, until recently, been a part of the culture. White Americans have been found to have lactose intolerance rates of 6 to 25%, while Black Americans have intolerance rates of 47 to 74% and American Indians and Eskimos 75% (Houts, 1988).
Lactose intolerance raises significant questions and problems such as the greater risk of malnourishment for low income groups which also show higher prevelence of the disease (Houts, 1988). Also, the question whether lactose absorption is necessary for utilization of the nutrients in milk (such as calcium) must be studied (Houts, 1988). In addition, the question of whether or not persons beyond the young-adult stage can become genetic lactose intolerant must be examined (Houts, 1988). If this is possible, then lactose intolerance will prevale -especially since the median age in the U.S. is increasing (Houts, 1988).
Consequently milk may not be considered a reliable source of nutrients for a large portion of the population, a fact that raises new public health concern (Houts, 1988).
In an ordinary diet, it is difficult for someone to -68-avoid lactose in unaltered forms, even if consumption of fresh dairy products is eliminated. Cooking the milk does not convert lactose to glucose or lactic acid; cream soups, puddings, cream pies and custards are not usually lactose free foods (Houts, 1988). In order to obtain a diet that would be discomfort-free yet nutritious, the lactose intolerant individual should consider options such as determining the threshold for the symptoms to occur and limit consumption of lactose to lower levels. Consumption of fermented foods is also suggested. During fermentation, J0-40% of the lactose is broken down and thus the lactose content is reduced (Scrimshaw et al., 1988). Products such as yoghurt and some natural cheeses (naturally aged Cheddar and Swiss cheeses) are either low in lactose or have inherent lactase activity (Houts, 1988;Martini et al., 1987;Scrimshaw et al., 1988). Another option is to add lactase to the fluid milk prior to its use. This process "predigests" major part of the lactose in milk making the milk product easily digestible for the lactase deficient person. Some of the suggestions made to the industry are to use lactose-reduced dairy ingredients in their processed foods and to manufacture a greater variety of lactosereduced dairy products for daily consumption (Houts, 1988).

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Ice cream is a pasteurized frozen dairy product made by freezing while agitating a mix of milk products, stabilizers, emulsifiers, flavors and other ingredients  . It is a complex food system where we have substances in true solution, others in colloidal suspension and the fat as an emulsion (Sommer, 1951). In true solution are, the milk salts, lactose, sucrose. In colloidal suspension there are, the milk proteins, gelatin, egg proteins (if eggs are used) (Sommer, 1951). Ice cream is a tasty and nutritious food. An average 100 gm serving supplies approximately 200 calories, 23.9 gm CHO, 10.8 gm fat and 3.6 gm of protein (Arbuckle, 1986).
Ice cream, among all other desserts available, is the one served more often in hotels and restaurants Leeder, 1981). It is very popular, especially in the  -71-1986, code of Federal Regulations, 1982. Ice cream must weigh not less than 4.5 pounds to the gallon. Microbial counts, acidity, along with optional dairy ingredients, fruits, flavors and other possible constituents are also covered under these standards , Code of Federal Regulations, 1982. Any product that does not satisfy these standards, can not be called ice cream.
There are standards for ice cream related products such as sherbets or ice milk, but there are also products that have been introduced in the market recently and do not clearly belong to any of these categories, (the most significant being frozen yogurt). These products fall in the category generaly described as "ice cream related products", or "frozen dairy desserts". Legislation that will cover all the new products is under review by the FDA since there is considerable pressure from the industry for standards that will ensure high quality products, and will protect the consummers.
The basic mix for the manufacture of ice cream is largely cream and other milk products, sweeteners, flavors and small amounts of functional ingredients such as stabilizers and emulsifiers . All ingredients of the mix are carefully blended in proper Proportions in a mixing tank. The mix then goes to a Pasteurizer where it is heated and held at a predetermined -72-temperature for a specific period of time, (the most common combination being HTST, at 79.5°C for 25 seconds) I.LC.A., 1988). The mix is then homogenized under pressure from 2,000 to 2,500 psi I.I.C.A., 1988). After homogenization, the hot mix is quickly cooled to about 4°C. Next, freezing of the mix is accomplished; while ice cream is being frozen, blades -commonly known as "dashers"-whip and aerate the product. The air uniformly whipped into the product as small air cells, is necessary to prevent ice cream from being too dense, too hard and too cold (Potter, 1978;r.r.c.A., 1988). The air, in the form of small air cells, is dispersed through the water-fat emulsion, acting as an insulator (A~buckle, 1986). Whipping during freezing causes increases in volume, known as overrun. The usual range of overrun in ice cream is from 70 to 100% Potter, 1978). (One liter of mix makes two liters of frozen ice cream with 100% overrun) . Following the freezing process, the packages are filled, and immediately placed in the "hardening room" where temperatures below -2o·c further harden the ice cream.
The quality o·f the individual ingredients used for the production of ice cream is important in determining the quality of the final product. As discussed below, each ingredient or processing step, contributes in a very -73-specific and unique way to the characteristics of the final product. (Table 15 summarizes the advantages and limitations of various ice cream constituents) .

Milkfat.
Milkfat, an ingredient of major importance to ice cream, is supplied by milk or cream Charley, 1982). The correct percentage of milkfat in the mix is essential not only to the quality of the final ' product, but also in meeting the legal standards, which require at least a 10% butterfat content (Arbuckle, 1986) .
Butterfat does not lower the freezing point of the mix; but it does increase the body of the final product and gives a smooth texture . By forming a mechanical barrier around ice crystals, butterfat affects ice crystal formation, so that more but smaller crystals are formed Charley, 1982). Milkfat enhances the flavor of ice cream. This is thought to be due to the fact that fat particles tend to concentrate toward the surface of air cells during the freezing process (Arbuckle, 1986).
Products with higher fat content will seem finer in texture due to lubricating effect of the fat droplets on the ice crystals (Charley, 1982). Fat content raises the caloric Value and the price of the product, both of which may be to achieve a higher overrun without snowy or flaky texture (Charley, 1982). MSNF is a low-cost way to increase the body and total solids (T.S.) of ice cream but care must be taken as too high a percentage of MSNF causes "sandiness" and may give the product a "condensed milk" flavor Charley, 1982) Sweeteners.
The sugar introduced into the ice cream mix enhances the taste, texture and flavor of the product. Sugar increases ice cream's acceptability not only by making the -76-product sweeter but also by enhancing the pleasing creamy flavor . The presence of sugar in the mix affects ice crystal formation in two ways. First, it lowers the freezing point, thus requiring lower temperatures for freezing and hardening (Charley, 1982). Secondly, sugar keeps the size of the ice crystals small by increasing the amount of liquid which remains unfrozen Charley, 1982). Added sugar, also increases the viscosity and the total solids of the mix . Above the 16% level, sugar tends to make ice cream soggy and sticky.
Also, excessive sweetness and extreme lowering of the mix's whipping ability may result from high concentrations of sweetener Charley, 1982). The sweeteners, along with fat, MSNF, stabilizers and emulsifiers, make up the total solids (T.S.) of the ice cream mix. When T.S. reach levels higher than 40 to 42%, the product is more likely to be soggy and undesirably heavy Charley, 1982).

Stabilizers.
Stabilizers are used in ice cream mixes to improve mix Viscosity, air incorporation, to slow down ice crystal formation, improve body and texture, melting properties, and especially to prevent a coarse and sandy texture from -77-temperature fluctuations during storage , Nielsen, 1984. Stabilizers are used in very small amounts and so they do not influence either the nutritional value or the flavor of the product. Stabilizers c9me from either animal or plant sources. When they are dispersed in water, they form a gel matrix with the available water molecules and in this way restrict the mobility of the water Nielsen, 1984). They have a high water-holding capacity, which contributes to improved body and texture of the product (Arbuckle, 1986) .
The amount of stabilizer used varies from O to 0.5%, according to its properties, the concentration of the T.S., the type of processing equipment and other factors . Excessive use of stabilizers will result in undesirable melting resistence and soggy body .
Stabilizing substances that are permited and used in the making of ice cream are agar, sodium alginate, gelatine, guar seed gum, locust bean gum, carrageenan, CMC, and others (Arbuckle, 1986). Emulsifiers.
These are substances which reduce the surf ace tension at the interface of two normaly immiscible phases, allowing -78-them to mix and form an emulsion (Dziezak J, 1988).
The reason emulsifiers are used in the manufacture of ice cream are to give the product a smoother texture, stiffer body and to reduce the whipping tii:ne (Arbuckle, l986). As the agitated freezing of the mix progresses and air is incorporated, the air cells become surrounded by an aqueous film containing dispersed milk proteins, which also contains emulsified fat and ice crystals (Charley, 1982).  Fennema, 1985).
The total amount of emulsifiers by weight may not exceed 0.2%. Dziezak J, 1988). Excessive use of such substances may result in slow and foamy melting, and textural defects (Arbuckle, 1986). -79-

National Ice cream and Yogurt Retailers Association
Project.
In order to further study frozen dessert products and to become acquainted with the commercial production and Uppon arrival, all samples were numerically coded and were immediately placed in the hardening room at -23°C.
The weight per volume for each sample was determined in two ways, as follows: a) The sample was first weighed along with its 1/2 gallon container. A similar 1/2 gallon ., container was then weighed empty, and from the diference, the gross weight of 1/2 gallon product was determined. This was multiplied by 2 to give the "lb/gal" value for the sample. b) A standard 1/2 cup measure, of known weight, was filled with sample and weighed. From the diference, the weight of 1/2 cup sample was determined. This was multiplied by 31.997 in order to give the "lb/gal" value of the product. In case of a large discrepancy between the results of two methods, the second method was repeated and that was the number recorded. Each sample shall consist of two (2) half-gallon packages. Samples shall consist of regular run products drawn from the freezer consecutively (samples for analysis and judging). Use plain containers so that the manufacturer may not be identified at the Clinic, manufacturer's name should appear only on the outside of the shipping container.
Samples packaged in unusual or mPrked packaging may be easily identified, therefore, any samples submitted in other than plain half gallon containers may be rejected.

OFFICIAL CONTEST FLAVORS
VANILLA CHOCOLATE All samples for the Clinic must be s hipped to arrive between Monday and Thursday, August 28-31, from 8:30 AM to 5:00 PM. and to contain a label; "Persons receiving and signing for package to immediately place in deep freeze or hardening room"(or a message to th i s effect so that package is not lying around at room temperature Pack with plenty of dry ice to provide 48 hours of frozen environment .
This will assure arrival of the samples in excellent condition.
A suggestion when shipping your samples by air freight, would be . to initiate Shipment in th~ late afternoon or early evening of the day before you wish the package to arrive at its destination. · usually the freight is handled more efficiently by the airlines during the night hours .

NOTE:
You are required to file two (2) copies of the "SHIPPER'S CERTIFICATION FOR RESTRICTED ARTICLES" with the air freight carrier as carbon dioxide (dry ice) is ident ifi ed as a restricted material.
Also, the shipping carton should be marked on at least three (3) sides with the identifying marks "ORM-A".
Results of analysis and judging will be given to you by a code.
The Judging of the samples will be done by a panel of trained and experienced judges in cooperation with Professor Clifford J. Cosgrove, University of Rhode Island, West Kingston, RI 02892. -82- The overrun for each sample was calculated through the "lb/gal" value and under the assumption that all mixes weighed 9.1 lb/gl before the freezing process. An example of the overrun calculation is given bellow:. Both the total plate count and the coliform count were done according to Post (1983). Violet red bile agar dehydrated and plate count agar dehydrated ware used, both by DIFCO Laboratories, Detriot, Michigan.
All of the above tests were run in duplicate. In case of a significant difference between the two readings, that specific sample was run in triplicate. Points were added to the total sensory score (max. 25.0 points}, according to bacteria count as follows: 5 points for TPC < 10,000 and coliform < 10.

4
" " 10,000 < TPC < 20,000 3 " " 20,000 < TPC < 30,000 2 " " 30,000 < TPC < 40,000 1 " " 40,000 < TPC < 50,000 0 " " 50,000 < TPC and / or coliform > 10. Measuring the overrun, the assumption for the weight of the mix was based on the late literature (Arbuckle 1986), where the figure of 9.1 lb/gai is the lowest average for commercial ice cream mixes. Keep in mind that 9.0 lb/gal is the lowest legal limit for an ice cream mix. The use of this figure in our calculations serves to the benefit of the contestants since for the same "lb/gal" of finished product, a heavier mix will give a higher overrun value.
All results have been tabulated and are included in the last 9 pages.
As far as fat and total solids are concerned, all -85-vanilla samples were within the legal limits. On the other hand, one chocolate sample was low in fat (9.8%) and one was low in both fat and total solids (9.5 & 33.4%).
Nine vanilla and six chocolate samples . ware bellow the 4.5 lb/gal legal limit and consequently, they were also judged to be high in overrun (higher than 100%, which is the highest legal limit).
The average values of all tests were very close between vanilla and chocolate samples, with the latter being slightly higher in pH values.
Six vanilla (18.7%) and eight (27.6%) chocolate samples gave high microbial count readings for either total plate or/and coliform.