Proximate Composition, Functional Properties, and Glycemic Index of Soybean (Glycine max) Enriched Carbohydrate Diets in Healthy Rats

glucose solution served as the standard (Jenkins et al., 1981; Wolever & Jenkins, 1986; FAO/WHO, 1997). 3.8 Statistical Analysis Data were analyzed using SPSS version 16.0 (SPSS Inc., Chicago, USA). Results were expressed as mean ± standard deviation (SD). One-way analysis of variance was used to compare means, and differences were considered statistically significant at p < 0.05. 4.0 Results 4.1 Proximate Analysis The results of the proximate analysis of the test food samples are as shown in Table 1 and 2 respectively. The proximate analysis on the processed food from Maize, Wheat, Guinea Corn showed crude protein, fat, ash content, moisture, crude fibre and carbohydrate as compared to the final mixture of the different flours mixed with soybeans in a ratio of 70:30 (w/g). Table 1 Proximate composition of flours on dry weight bases (g/100g) Composition Maize Wheat Guinea Corn Crude Protein (g%) 9.19 12.0 7.0 Fat/Oil (g%) 4.43 1.39 2.45 Ash (g%) 1.12 1.32 1.30 Moisture (g%) 9.01 9.25 11.04 Crude Fibre (g%) 1.36 1.00 2.00 Carbohydrate (g%) 74.84 75.04 76.21 Table 2 Proximate composition of flours on dry weight bases (g/100g) after mixing with soybeans Composition 70% Maize + 30% Soy Beans 70% Wheat + 30% Soy Beans 70% Guinea Corn + 30% Soy Beans Crude Protein (g%) 21.13 27.81 26.94 Fat/Oil (g%) 6.20 7.76 6.66 Ash (g%) 2.89 2.69 2.60 Moisture (g%) 12.70 12.86 12.99 Crude Fibre (g%) 4.06 4.67 5.30 Carbohydrate (g%) 53.02 44.21 45.51 , 4.2 Functional Analysis The result of the functional analysis as stated in chapter 3 is as shown inTable 3. Table 3 Functional analysis of the various food samples SAMPLE SWEL LING INDEX BULK DENSIT Y OIL ABSORPTIO N CAPACITY WATER ABSORPTIO N CAPACITY GELATION CAPACITY Maize 9.19 0.63 1.40 2.2 6% Wheat 12.00 0.68 1.60 1.6 10% Guinea Corn 1.33 0.67 1.20 2.1 10% NB: All samples were mixed with Soy Beans in the ratio of 70:30 (w/g) 4.3 Mean Blood Glucose Response of Glucose Tables 4 and 5 shows the mean glucose response on the first and second day after tail tipping four rats while figures1 and 2 show the graphical representation of the glucose response area; There was no significant difference between the glucose responses on both days (P<0.05) Table 4 Glucose response day 1 Time 0 20 40 60 90 120 Mean (mg/dL) 92.50 1.98 1.22 3.94 3.23 1.78 Table 5 Glucose response day 2 Time 0 20 40 60 90 120 Mean (mg/dL) 1.08 1.25 1.23 1.04 80.7 81.00 4.4 Mean Wheat Response Tables 6 and 7 shows the mean blood glucose responses after subjects were fed with wheat on two separate days at different time intervals while figures 3 and 4 illustrates the response curves after consuming the meal.There is no significant difference (P<0.05) between the blood glucose responses on both days. Table 6 Wheat response day 1 Time 0 20 40 60 90 120 Mean (mg/dL) 67.75 1.65 1.38 1.16 1.17 1.35 Table 7 Wheat response day 2 Time 0 20 40 60 90 120 Mean (mg/dL) 85.50 1.27 1.09 1.04 1.02 1.02 , 4.6 Guinea Corn Response The mean results from the glucose response after the subjects were fed with Guinea Corn is shown on tables 8 and 9; it is also shown on figures 5 and 6 that there is no significant difference (P<0.05) in the glucose response after the two days. Table 8 Guinea Corn response day 1 Time 0 20 40 60 90 120 Mean (mg/dL) 75.00 89.50 89.75 73.50 50.50 57.25 Table 9 Guinea Corn response day 2 Time 0 20 40 60 90 120 Mean (mg/dL) 75.00 89.50 89.75 73.50 50.50 57.25 4.7 Mean Maize response Tables 10 and 11 shows the glucose responses of the experimental subjects after being fed with maize for a two-day period. The graphical presentation of the responses are as shown in figures 7 and 8 it would be observed that there is no significant difference in the responses after the two-day period of consuming the food sample by the subjects. Table 10 Maize response day 1 Time 0 20 40 60 90 120 Mean (mg/dL) 1.10 1.35 1.24 1.17 1.53 1.13 Table 11 Maize response day 2 Time 0 20 40 60 90 120 Mean (mg/dL) 84.75 1.16 1.24 1.22 1.15 1.18 4.8 Incremental Area Under the Curve and Glycemic Index calculation and Statistics. The IUAC and Glycemic Index is calculated as illustrated in figure 4.11 and the calculations that follow; the results are as shown in table 12; it will be observed that there is a significant difference in the glycemic index values of the 3 food samples on both days as maize and wheat showed a high glycemic index while Guinea Corn had a low Glycemic index. Table 12 Mean blood glucose response for Guinea Corn Day 2 Time 0 mins 20 mins 40 mins 60 mins 90 mins 120 mins Mean(mg/dL) 141.5 159.25 120.25 111.75 230.00 91.00 , Table 13: IUAC of Food Samples Food Sample IUAC Day 1 Day 2 Wheat 326.19 137.93 Guinea Corn 34.53 31.75 Maize 180.24 190.55 Glucose 116.44 119.09 Table 14: Glycemic Index of Food Samples Food Sample Glycemic Index Day 1 Day 2 Wheat 280.14 91.23 Guinea Corn 29.65 26.66 Maize 154.79 160.01 4.9 Effect of Glucose response against Days The effect of glucose response against days is as presented in table 15. It will be observed that there is a significant difference in the blood glucose response with increase in time. Table 15: Glucose Response (mg/dL) against Days TIME MEAN ± S.D 0 MINS 1.01 ± 29.46ab 20 MINS 1.35 ± 37.51ab 40 MINS 1.19 ± 28.80ab 60 MINS 1.08 ± 30.23ab 90 MINS 1.35 ± 98.43ab 120 MINS 98.75 ± 34.22b Values were expressed as Mean ± S.D, n = 1. Values with the same alphabets are not significantly different from each other. The values are significantly different at p < 0.05. 4.10: Effect of Glucose response against Treatment The results of the blood glucose response with respect to the food samples are as presented on table 16. , Table 16: Glucose Response (mg/dL) against Treatment TREATMENT MEAN ± S.D GLUCOSE 1.43 ± 11.45b GUINEA CORN 88.10 ± 31.59a MAIZE 1.19 ± 23.36b WHEAT 1.14 ± 35.99b Values were expressed as Mean ± S.D, n = 1. Values with the same alphabets are not significantly different from each other. The values are significantly different at p < 0.05. 4.11: Effect of Glucose response against Days The results for the effect of glucose with respect to the period of administration is as shown on table 17. Table 17: Glucose Response (mg/dL) against Days DAYS MEAN ± S.D Day 1 1.24 ± 52.51a Day 2 1.09 ± 49.15a Values were expressed as Mean ± S.D, n = 1. Values with the same alphabets are not significantly different from each other. The values are significantly different at p < 0.05. 5.0 Discussion, Conclusion and Recommendation 5.1 Discussion Before foods are consumed either by man or by rats, they are generally processed. The processing methods include cooking, (i.e. boiling, roasting, frying, steaming, baking, autoclaving), drying, mashing, grinding into flour and fermentation. In this study, the test foods were basically dried, milled into flour, sieved and then reconstituted to paste with hot water. Thus the particle sizes were reduced into fine particle sizes and the starch was retrograded (gelatinized) to a variable extent to improve the palatability of the food. These treatments might have led to their having high glycemic indices (Ludwig, 2003; Bjork and Elmstahl, 2005). This is similar to reports that increased processing and starch retrogradation can affect GI (Foster-Powell et al., 2002). 5.1.1 Influence of Other Factors on Glycemic Index It has been well established that different carbohydrate foods elicit a wide spectrum plasma glucose response when eaten without other foods (Collier et al., 2002). Recently, Geoffery et al. (2008) found that lower glycemic index (GI) diets reduced both fasting blood glucose and glycated proteins independently of variance in available and unavailable carbohydrate intakes. , It would be observed in table 4.12 that Wheat and maize produced a high glycemic index result while Guinea corn showed to have a low Glycemic index. As shown in table 4.12 it will also be seen that there was a significant difference in the glycemic indices of all three food samples with wheat having the highest glycem