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The controversial condition of carbohydrate craving is believed by some researchers to be a defect in the regulation of food intake by an individual. This defect is believed to be responsible for the inability of some persons to control their food intake and therefore their weight. Research was conducted to test the hypothesis that, given a group of carbohydrate cravers and a group of noncravers, the cravers will experience a greater plasma insulin response (concentration and area under the curve) than will the noncravers, and that, because of this higher response, the cravers will experience equal or lower plasma glucose levels during a carbohydrate load. A second hypothesis was that, because of cephalic insulin response due to sensory stimuli, cookies would elicit a greater plasma insulin response than would a glucose solution. This higher plasma insulin response may in part explain the uncontrollable snacking that some individuals experience. The purpose of this research was to attempt to identify a biochemical distinction between persons who crave carbohydrates and persons who do not crave carbohydrates. Eleven overweight female subjects, age 30 to 40, were recruited and divided into two groups, five carbohydrate cravers and six noncravers, based on scores received on a questionnaire that was devised for this study to attempt to distinguish between the groups. A Restrained Eating questionnaire was also administered to the subjects. Both groups had similar, but high, restrained eating scores, indicating that all of the subjects were probably restrained eaters. The eating restraint, as supported by the reported frequency of dieting among the subjects, may well have influenced the subjects' responses to the carbohydrate craving questionnaire. Utilizing these two groups of subjects, two tests were administered. The oral glucose tolerance test was administered, utilizing 75 g of carbohydrate each in the forms of glucose solution and cookies, which were administered in a random order. The tests were administered during the premenstrual phase of the subjects' menstrual cycles, 0-10 days prior to the onset of menstruation. Blood was drawn and assayed for plasma glucose and insulin. The research showed that the cravers experienced a significantly greater plasma insulin concentration and area under the curve than the noncravers, particularly at the 30, 60 and 120 minute time points with the glucose treatment. For the glucose treatment, the cravers experienced plasma insulin concentrations that were 32% to 50% greater than those of the noncravers in the early portion of the test. This supports the hypothesis which states that cravers will experience a greater plasma insulin response to a carbohydrate load than will noncravers. This elevated plasma insulin level may be responsible for the carbohydrate cravings that the individuals experience. There was no significant difference in plasma glucose levels at any time point in either of the tests as compared between the cravers and noncravers, thus supporting the expectation that these levels would be similar between the groups. The hypothesis that cookies would elicit a greater plasma insulin response than would a glucose solution was not supported. Any cephalic insulin response which may have resulted from the sight and smell of the cookies, while not specifically measured, was not strong enough to override the physiological factors that control insulin release. Therefore, the glucose solution elicited a significantly greater plasma insulin concentration than did the cookies in the cravers during the first two hours of the tests, and a significantly greater area under the curve for the cravers at 60 minutes and both groups at 120 minutes. However, the cookies did have an effect on insulin release at the fasting point, causing elevated (x = 79%) plasma insulin levels in three of five subjects who were waiting while others were eating the cookies, as compared with these subjects' fasting insulin levels when they were not exposed to the cookies prior to their glucose test. Another finding was a difference between the groups in fasting plasma insulin concentrations over the 10 day premenstrual portion of their menstrual cycles. The noncravers experienced fasting plasma insulin concentrations that decreased as the onset of menstruation was approached, which would parallel the decrease in progesterone levels. However, the cravers experienced first a decrease in fasting plasma insulin levels to day 3 premenstrual, and then an increase to the level of that found 8-10 day premenstrual. This pattern is contrary to what would be expected as progesterone levels drop, and suggests an altered pattern of progesterone levels in the cravers, although progesterone was not measured in this study. To summarize, in a group of overweight women, carbohydrate cravers and non cravers, the cravers experienced a greater plasma insulin response than did the noncravers for the glucose treatment but not for the cookie treatment, and there was no significant difference between the groups for plasma glucose concentration for either treatment. / Graduation date: 1991

Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2013. / Acha starch was isolated and purified from clean and milled acha grain. Functional, thermal and physicochemical properties of acha starch were analysed using appropriate methods. Wheat starch was used as the reference standard. Acha bread from acha grain was baked and the consumer sensory acceptability was evaluated and white wheat bread was used as the reference standard. The effect of baking, boiling, steaming and microwaving on the starch and glycemic properties of the acha starch was evaluated. With regard to thermal properties, gelatinisation temperature of acha and iburu starches typifies that of waxy starch. Acha starch has similar retrogradation temperature profiles as that of wheat. There were however significant differences in some of the functional properties (pasting and turbidity) and physico-chemical properties (in vitro starch digestibility), but no significant difference in the texture profile analysis (TPA) and water binding capacity (WBC). WBC of both acha varieties was higher than that for wheat starch. Due to its high break down viscosity, white acha starch can be included in foods that are subjected to high temperature processing. This indicates that both acha starch varieties can be used for hot and cold desserts as well as for soft jelly like sweets and confectionery toppings. A prescreening exercise using carboxymethyl cellulose (CMC), Xanthan gum, yeast and acha starch as the variables was successful in concluding a recipe which rendered acha bread with the optimum specific loaf volume for both white and black acha bread. The optimum recipe consisted 8.0 % acha starch, 2.0 % xanthan gum, 2.0 % CMC and 1.0 % yeast. The majority of the consumer panellists found the crust colour, taste and aroma to be moderately desirable. This implies that most consumers find acha bread to have the potential to be marketed as wheat free bread. The different processing methods baking, boiling, microwaving and steaming, affected the black and white acha starch hydrolysis. The amount of starch hydrolysed for the different processing methods was in the following order: baking > boiling > microwaving > steaming. It can thus be concluded that different processing methods affects the micro structure and physical properties of the acha and wheat samples which thus influence their starch hydrolysis. The equilibrium percentage of starch hydrolysed after 180 min incubation was affected differently for the various starches, black acha, white acha and wheat starch by the different processing methods and times. In the case of baking black acha starch and wheat bread were affected similarly. However, this was not the case for microwaving, steaming and boiling, where both acha starch varieties and wheat starch were affected in the same way. The rate of starch hydrolysis for both acha varieties and wheat grain for the different processing methods, steaming, boiling, microwaving and baking was affected to the same degree respectively.