The aim of this work was to study proteolytic activity of actinidin in comparison with chymosin and ficin on bovine milk substrate. The specific activities of purified ficin and actinidin were 7.9 and 8.3 unit/mg protein, respectively. The optimum clotting activity of both actinidin and ficin was at 45°C, although chymosin was relatively less sensitive to temperature. Increasing CaCl2 concentration resulted in an enhancement of the clotting activities of all coagulating enzymes, this effect noticeable for ficin. In ficin treated sample significant decrease of bands intensity in the range 25-30 KD and appearance of some of κ-casein in 20 KD regions was observed by using SDS-PAGE. In conclusion, the chymosin and actinidin gave similar relative activity at different temperatures, pH values and CaCl2 concentrations for bovine milk substrate. Comparable electrophoresis profile of actinidin, ficin and chymosin by analysis of the whey with SDS-PAGE indicates that actinidin could be a potential alternative for chymosin.
Glycemic indices (GIs) and insulin responses are useful for measuring biological effects and consequences of carbohydrates when designing healthy diets, particularly for people with or at risk of developing diabetes and others disorders such as metabolic syndrome. In this study, we investigated GIs and insulin (as measured by C-peptide) responses of patients with type 2 diabetes mellitus (T2DM) to Bangladeshi potatoes and sweet potatoes. Using a cross-over design, ten T2DM subjects consumed equivalent carbohydrate amounts (50 g of total carbohydrate) of either the vegetables or white bread (WB) (as reference food). Serum glucose levels were determined after 0, 15, 30, 45, 60, 90, 120, 150 and 180 minutes, and C-peptide levels were determined at 0 and 180 minutes. Glycemic Indices and Glycemic Loads (GLs) were calculated. Both plain and sweet potatoes showed a significantly higher serum glucose response compared to the reference food. The similar glycemic response between plain and sweet potatoes was reflected in their GI values: 162 ± 50 and 191 ± 66, respectively. The GL values were 8 and 11, respectively. The substantially higher glycemic response and GI values of the two potatoes were not the consequence of a suppressed insulin response. Compared to the mean values of the international table, Bangladeshi potatoes and sweet potatoes are very high GI foods. However, based on the dietary practices in our society, potatoes and sweet potatoes may be used as low and medium GL foods, respectively. This work may help create a better food exchange table for diabetic patients.
This study was aimed to investigate the effects of chemical treatment as well as pasteurization on the shelf life of “kunun zaki” (a non-alcoholic beverage commonly consumed by the people of northern Nigeria), to increase the shelf life and preserve the quality of the beverage. Kunun zaki was produced by dry -cleaning, washing, steeping (sorghum for 24 hours and maize for 48 hours), malting for 72 hours at room temperature, wet milling, mixing, cooking and filtering to obtain the liquor. The product was treated with 0.1% sodiumbenzoate or sodium metabisulphite or their combinations. These were packed and pasteurized in bottles at 60°C for one hour. Another batch of samples were chemically treated but not pasteurized. Pasteurized samples which were not chemically treated served as control. Samples were stored at ambient temperature and monitored for changes in pH, titratable acidity, total solid, total sugars, acceptability and colour for four weeks. The pH and sugar decreased and the decrease was more pronounced in non pasteurized samples irrespective of chemical treatment. Titratable acidity increased in all samples with storage time. Pasteurized kunun zaki which received no chemical treatment deteriorated after one week of storage. Samples treated with 0.1% sodium benzoate or sodium metabisulphite or their combination without pasteurization deteriorated after two weeks of storage. Samples which were similarly treated and pasteurized were stable for more than three weeks. Pasteurization enhanced effectiveness of chemical preservation and acceptability of kunun zaki.
Selected traditional Nigerian diets: Garri with afang soup, pounded yam with edikang ikong soup and ekpang nkukwo alongside a reference diet, plantain with beans porridge, were investigated for their efficacy for use in management of diabetes mellitus. The proximate composition of the diets was analysed using standard methods and thereafter fed to alloxanized rats for 15 days, while monitoring the changes in weight and blood glucose. Fasting blood glucose (FBG) results was significantly reduced (p<0.05) (initial and final) upon feeding garri with afang soup (25.61%) and pounded yam with edikang ekong soup (25.19%) relative to the diabetic control (5.19%). These reductions compared well with the reference diet, although its extent of glycaemic control was higher (37.22%). Body and relative liver weight changes over the period animals received the traditional diets were not significantly different (p>0.05) from that of the reference diet. Whereas the proximate composition components including crude proteins, fibre, ash and carbohydrate were not significantly different (p>0.05) compared to the reference diet; only crude fat and hence caloric value was significantly higher (p<0.05) in reference diet compared to the three traditional diets. From the results of this investigation, it is clear that the traditional diets studied can be effective in glycaemic control, hence could serve as effective substitutes for plantain with beans, usually recommended by health care givers.
Background: Popcorn is cereal grains originated from a wild grass (Zea mays everta). Human consume popcorn as snacks. Popcorn provides a full complement of nutrition benefits, including dietary fibre, protein and essential micronutrient. Processing methods, such as, sprouting and fermentation improved the nutritional quality of cereals and legumes. In view of this, the present study, therefore, investigates the influence of germination and fermentation on nutrient composition, choking property and functional property of popcorn. Methodology: The popcorn kernels were obtained from a local market in Akure, Nigeria. The popcorn kernel was divided into three portions. Two portions were subjected into germination and fermentation respectively, while the third portion was processed as raw sample. Each of the samples was milled, sieved and analysed for proximate, minerals, amino acids and fatty acids using standard methods. Also, the functional and choking properties of the processed flour were determined using standard methods. Results: The result showed that the protein content of popcorn flour samples ranged between 12.13±0.56 - 14.37±0.52 g/100g; while the energy value was between 322.53±8.91 and 421.93±5.58 Kcal. The phosphorous, potassium, sodium, magnesium, iron and zinc content of germinated popcorn flour (GPF) were higher than fermented popcorn flour (FPF). The total amino acids content of the sample range between 13.52 - 26.55 mg/100g for essential amino acids, 28.08 - 40.57 mg/100g for conditional essential amino acids; while 20.90 - 23.71 mg/100g for the non-essential amino acids. The nutritional quality results were as follows: protein efficiency ratio (PER) range between 0.88 and 1.55, essential amino acid indices (EAAIs) was between 13.62% and 44.18%; while the biological values (BV) was between 3.15% and 36.45%. The overall dominant fatty acid in each of the samples was oleic acid (67.05501 mg/100g) for the raw popcorn flour (RPF), palmitic acid (50.42259 mg/100g) for GPF and linoleic (68.72825 mg/100g) for FPF; while the dominant polyunsaturated fatty acids in RPF, GPF and FPF samples was linoleic. For the functional property, the results showed that swelling capacity range between 4.224±0.005 and 4.958±0.020. Bulk density was between 0.783±0.001 and 0.821±0.012; while that of water absorption capacity was between 1.964±0.014 and 2.111±0.044. The protein solubility of the samples increased in both above and below pH 2 for RPF and GPF sample and pH 3 for FPF sample, i.e., at the isoelectric points. For sensory attributes, the FPF was significantly rated higher in the overall acceptability than GPF, but rated lower than the ‘ogi’ (a sweet corn gel). Conclusion: The present study evaluates the amino acid profiles, fatty acids composition, choking property and functional property of RPF, GPF and FPF. The result showed that germination and fermentation processing techniques improved on the nutrient composition and also, eliminate the choking property of the processed popcorn flour. In view of this, the germinated or fermented popcorn flour may be used as traditional breakfast meal (ogi) or in the formulation of complementary foods.
The term “probiotics” (meaning “for life” in Greek) refers products containing live microorganisms, which increase the population of friendly intestinal bacteria upon ingestion. Several new dairy product formulations containing probiotic cultures are being developed with such microbes which when consumed offer potential health benefits viz. increased resistance to infectious diseases - particularly of the intestine, decreased duration of diarrhea, reduction in blood pressure, reduction in serum cholesterol concentration and allergy, stimulation of phagocytosis by peripheral blood leucocytes, modulation of cytokine gene expression, adjuvant effects, regression of tumors, reduction in carcinogen products, increased tolerance to lactose in lactose intolerant population etc. In addition, all potential benefits could not be achieved from just one type or strain of organism. Examples of probiotic microorganisms used in foods include Lactococcus lactis, Lactobacillus sp., Streptococcus, Enterococcus, Bifidobacterium sp., Pediococcus, Propionibacteria sp. This review paper highlights the benefits, technological aspects, world scenario and limitations of probiotic foods.