Effect of domestic processing on the cooking time,nutrients, antinutrients andin vitro Protein digestibility of the African yambean (Sphenostylis stenocarpa)

The effects of processing (soaking, dehulling, fermentation and heat treatment) on the cooking time, protien, mineral, tannin, phytate and in vitro protein digestibility (IVPD) of the african yambean (AYB) were examined. The cooking time ranged from 90–155 minutes. Soaking reduced cooking time by about 50 percent. Soaking for 12 hours was the most appropriate to reduce cooking time, tannin and phytate levels. It improved in vitro protein digestibility (IVPD). Prolonged soaking (24 hours) decreased calcium (Ca) and iron (Fe) values by 19 percent and 35 percent, respectively. Dehulling showed that Ca, Fe, magnesium (Mg) and zinc (Zn) were concentrated in the seed coat of the AYB. The seeds soaked and dehulled retained Mg and Zn. Dehulling reduced tannin but had no significant effect on phytate and the IVPD of the AYB except for seeds soaked for 12 hours before dehulling. Soaking for 24 hours before dehulling significantly increased crude protein content by 16 percent (p<0.05). Blanching and roasting increased the IVPD by 8–11 percent. Fermentation had no effect on the crude protein, Ca, Fe, Mg and Zn but significantly reduced phytate content of the AYB. Fermentation had no advantage over heat treatment with respect to improving the in vitro protein digestibility of the AYB.     

Effect of domestic processing,cooking and germination on the trypsin inhibitor activity and tannin content of faba bean (Vicia faba)

The effects of domestic processing methods like soaking for 12 h dehulling, ordinary cooking of whole as well as dehulled seeds at 151bs/inch² pressure for 15 and 25 min, and germination for 24, 36 and 48 h were observed on trypsin inhibitor (TIA) and tannin content of two varieties of faba bean viz. VH-131 and WF. A non-significant reduction in TIA was observed on soaking and dehulling, while tannins showed a reduction of 42 and 51% on soaking in VH 131 and WF, respectively. Dehulled seeds showed a decline in tannin content by 70 to 73% in two varieties. There was a significant reduction in TIA (75–76 per cent) and tannin (76–81%) on cooking, while autoclaving for 25 min almost completely eliminated both of these stress factors. Germination of seeds for 48 h led to a reduction of 64–65% in TIA and 90–91% in tannins, which was more than germination for 24 and 36 h. Soaked seeds gave positive results of both these antinutrients.     

Studies on α-amylase and trypsin inhibitors in legume seeds using agar diffusion and isoelectric focusing techniques

Amylolytic and tryptic inhibitors of faba bean extracts were determined by an agar diffusion test. The amylolytic inhibitor had protein characters. Furthermore, water-soluble trypsin inhibitors ofCicer arietinum, Lens esculenta, Lupinus termis, Phaseolus vulgaris, Pisum sativum, Trigonella foenum-graecum andVicia faba which were separated by polyacrylamide gel isoelectric focusing (PAGIF) in thin-layers, showed species specific patterns. Negative staining showed 10 bands for French beans, 9 for fenugreek seeds, 8 for lentils and chickpeas, 7 for peas and 6 for faba beans. Lupin seeds were free from trypsin inhibitors. Treatments (soaking, germination and heat processing) of faba beans reduced the number of trypsin inhibitors in PAGIF patterns, less after soaking and germination, but more after roasting and frying. No inhibitors were detected after cooking.     

Effect of soaking,sprouting, fermentation and cooking on nutrient composition and some anti-nutritional factors of sorghum (Guinesia) seeds

This study was designed to determine the effect of soaking, sprouting, fermentation and cooking on nutrient composition and some antinutritional factors of sorghum seeds (guineesia). Standard assay procedures were adopted to resolve both the nutrients and the antinutritional factors content of the products. Combination of cooking and fermentation improved the nutrient quality and drastically reduced the antinutritional factors to safe levels much greater than any of the other processing methods tested.     

Trypsin inhibitor in moth bean: thermal stability and changes during germination and cooking

Trypsin inhibitor from moth bean was studied for thermal stability and changes during germination and cooking. The application of dry heat did not inactivate the inhibitor. However, autoclaving at 120°C at 15lbs pressure destroyed inhibitor activity completely. The extracted inhibitor lost 70% activity in 60 min when incubated at 100°C. Soaking of moth bean seeds for 8 h decreased trypsin inhibitor activity by 20%. The germination of seeds for 24 h resulted in 70% reduction in inhibitor activity. No activity was detected in 48 h germinated seeds. Germination (for 24 h) followed by cooking of moth bean seeds destroyed the trypsin inhibitor completely.     

Chemical composition and nutritional potential of yam bean seeds (Pachyrhizus erosus L. Urban)

Pachyrhizus erosus seeds were analysed for proximate composition, minerals, protein fractions, antinutritional factors, and rotenoids. The seeds showed a high content of proteins, lipids, Fe and Ca, in comparison to other legumes. Glutelins constitute the highest protein fraction, followed by globulins. Antinutritional substances detected as tannins, hemagglutinating activity and trypsin inhibitory activity, were in low concentrations. Seeds were also processed to obtain a flour which showed proper characteristics, good in vitro digestibility, significant rotenoid reduction level and amino acid composition rich in essential amino acids, except methionine.     

Changes in trypsin and chymotrypsin inhibitory activity on soaking of sorghum (Sorghum bicolor L. Moench)

Changes in trypsin and chymotrypsin inhibitory activity of sorghum (Sorghum bicolor L. Moench) seeds on soaking in distilled water, different salt solutions and mixed salt solution were investigated. A greater reduction in proteinase inhibitory activity was observed on soaking in salt solution than on soaking in distilled water. Maximum loss of trypsin and chymotrypsin inhibitory activity was observed on soaking seeds in mixed salt solution.     

Evaluation of the effect of processing techniques on the nutrient and antinutrient contents of pearl millet (Pennisetum glaucum) seeds

This work was undertaken to evaluate the effect of soaking, sprouting, cooking and fermentation or their combinations on the nutrient and antinutrient contents of pearl millet seeds. Standard assay procedures were adopted to determine both the nutrient and the antinutrient concentrations of the products. The synergistic effect of cooking and fermentation improved the nutrient quality. The antinutrients were reduced to safe levels to a greater extent than did any of the other processing techniques or their combinations employed.     

Soaking and cooking parameters of tepary beans: effects of cooking time and cooking temperature on hardness and activity of nutritional antagonists

Tepary samples were examined for patterns of hydration, dry matter losses during the processes of soaking and cooking, residual hardness in partially cooked samples and heat lability of endogenous proteinaceous antinutritional factors. At 24 °C, teparies imbibed water equivalent to their weight (100% hydration) in 4 h and continued to absorb water rapidly for an additional 4 h before reaching an equilibrium hydration. During the processes of soaking and cooking, materials leached from raw beans represented 7.3 and 13.5% of their dry weight, 4.3 and 12.4% of their protein content, 7.1 and 12.2% of their stored carbohydrate and 22.4 and 33.4% of their mineral levels, respectively. In samples prepared at different cooking times (60, 90, 120, 150, 180 min) and cooking temperatures (80, 85, 90, 95°C), longer times and higher temperatures resulted in greater reductions in residual bean hardness; interactive effects of time and temperature treatments were significant. Residual activity of trypsin and chymotrypsin inhibitors in partially-cooked samples appeared to be negligible. In addition, at least 80% of the original hemaglutinating activity of lectins in raw beans was lost during partial-cooking of samples under all cooking regimes.     

Effect of alkali treatments on the nutritive value of common bean (Phaseolus vulgaris)

The effect of alkali treatments of common bean seeds with red seed coat on the stability of antinutritional factors such as tannins, phytates and trypsim inhibitors, vitamins such as niacin and riboflavin and on protein quality has been studied. The samples were processed by soaking and soaking and pressure cooking in alkalies such as sodium hydroxide, sodium carbonate and sodium bicarbonate. At low temperature sodium carbonate and at high temperature sodium bicarbonate were found to be most effective in the extraction of tannins. At both low and high temperatures sodium carbonate was found to be more efficient in destruction of phytates. In the case of trypsin inhibitors, extraction at both low and high temperatures with sodium bicarbonate was most effective. Sodium hydroxide treatment was found to be better as far as the retention of niacin and riboflavin was considered.     

Changes in trypsin and chymotrypsin inhibitory activity on soaking of redgram (Cajanus cajan L.)

Changes in trypsin and chymotrypsin inhibitory activity of redgram seeds on soaking in distilled water, different salt solutions and mixed salt solution were investigated. Reduction in trypsin and chymotrypsin inhibitory activity was observed on soaking in salt solutions in comparison to soaking in distilled water. Maximum loss of trypsin and chymotrypsin inibitory activity was observed on soaking the seeds in mixed salt solution.     

Studies on amylase inhibitors in some Egyptian legume seeds

Amylase inhibitor activity was determined in four legume seeds which are widely consumed in Egypt. The effect of dehulling, heat treatment, soaking and germination were also assessed. The results showed that faba bean contained the highest activity of amylase inhibitor followed by cowpea, lentils, then chickpea. Dehulling resulted in raising the amylase inhibitor activities in all samples investigated, while heat treatment and cooking lowered it. Soaking for 10 h and germination eliminated completely the inhibitor from all samples.     

Protein digestability of vegetables and field peas (Pisum sativum)

Protein digestibility was found to be 60.4 to 66.5 percent in raw unprocessed seeds of different pea cultivars. Protein digestibility (in vitro) was improved by the common methods of domestic processing and cooking including soaking, dehulling, ordinary cooking, pressure cooking and sprouting of legume grains. Pressure cooking had more pronounced effect on protein digestibility followed by ordinary cooking, sprouting, soaking for 18 h and (12 h) and dehulling. Pressure cooking of soaked and dehulled seeds was noticed to give most improved protein digestibility.     

Antinutrients in amphidiploids (black gram × mung bean): varietal differences and effect of domestic processing and cooking

Phytic acid, saponin and polyphenol contents in grains of various varieties of black gram (Vigna mungo) Mung bean (Vigna radiata L.) amphidiploids ranged from 697 to 750, 2746 to 2972 and 702 to 783 mg/100 g, respectively. Domestic processing and cooking methods including soaking, ordinary and pressure cooking of soaked and unsoaked seeds, and sprouting significantly lowered phytic acid, saponin and polyphenol contents of the amphidiploid seeds. Soaking for 18 h removed 31 to 37% of the phytic acid; the extent of removal was higher with long periods of soaking. Saponins and polyphenols were relatively less affected. Loss of the antinutrients was greater when soaked instead of unsoaked seeds were cooked. Pressure cooking had a greater effect than ordinary cooking. Antinutrient concentrations declined following sprouting; the longer the period of germination the greater was the reduction.     

Effects of heat treatments on trypsin inhibitor and hemagglutinating activities in winged bean

The effect of different heat treatments on inactivation of trypsin inhibitor and hemagglutinin of winged bean was investigated. Trypsin inhibitor extracted from winged bean meal was stable at 60 °C for 60 min. At 80 °C, the activity of the extracted inhibitor decreased by 25% within 5 min, and continued to decline gradually to a loss of 45% of activity after 30 min. When the extracted inhibitor was incubated at 100 °C, it exhibited a triphasic pattern of inactivation. The winged bean extract incubated at 60 °C lost 60% of its hemaggluinating activity within 30 min. At 80 °C, there was a complete loss of activity within 5 min. The microwave treatment to winged bean meal had no effect on trypsin inhibitor or hemagglutinating activities in the meal. However, infrared treatment to winged bean seeds for 60 seconds was effective in destroying most of the trypsin inhibitor and hemagglutinating activities. Autoclave treatment (120 °C at 15 lb pressure) for 10 min inactivated trypsin inhibitor and hemagglutinin in winged bean meal almost completely. Cooking of presoaked beans in boiling water for 30 min was effective in destroying most of the trypsin inhibitor and hemagglutinating activities.     

淀粉老化调控对燕麦全粉挤压面条蒸煮品质的影响

燕麦粉不含面筋蛋白,使燕麦全粉面条煮熟后易浑汤、蒸煮损失率大,目前只能温水浸泡复水食用,是限制燕麦更广泛推广的难题之一。为了满足市场对燕麦全粉面条的需求,以利用二级挤压技术生产的燕麦全粉挤压面条为试材,对成型面条进行了调湿老化、蒸制老化及冷冻老化处理,比较了不同老化方式对燕麦全粉挤压面条蒸煮品质的影响。结果表明,调湿老化处理的面条蒸煮损失率最小(2.26%~3.34%),蒸制老化次之(4.19%~5.19%),冷冻老化最大(5.16%~7.97%)。不同老化处理的面条感官评分差异不显著,以调湿老化处理24h的面条感官评分最高(87.2分);调湿老化处理面条的淀粉相对结晶度(12.47%~16.10%)、热焓值(1.044 0~1.056 0J·g-1)及回生值(519.5~558.0cP)均最大,蒸制老化次之,冷冻老化最小。综合分析可知,对燕麦挤压面条进行淀粉老化处理,能够显著降低燕麦全粉挤压面条的蒸煮损失率,最优方式为调湿老化24h。     

醋制对黑豆蛋白含量及多肽ACE抑制活性的影响

为考察醋制对黑豆蛋白含量及多肽ACE抑制活性的影响,为对黑豆醋浸过程中蛋白组分及含量变化进行分析,并对相应ACE抑制肽活性进行测定。黑豆经醋浸不同时间后,采用顺序抽提法提取清蛋白、球蛋白、醇溶蛋白和谷蛋白,并采用凯氏定氮法及SDS-PAGE电泳进行定量和定性分析;各蛋白组分经胃蛋白酶水解,经超滤(截留分子量3 k D)后收集滤液,获得多肽组分,RP-HPLC法进行ACE抑制活性评价。结果表明:经醋浸14 d后,黑豆总蛋白含量变化幅度小于±0.5%;清蛋白含量由55.13%(0 d)降低至9.61%(14 d);球蛋白由7.04%(0 d)增加到20.34%(14 d);醇溶蛋白由0.81%(0 d)增加到1.72(14 d);谷蛋白由21.11%(0 d)增加到59.45%(14 d),含量最高。醋浸处理降低了清蛋白源多肽的ACE抑制活性,但提高了球蛋白、醇溶蛋白及谷蛋白多肽的ACE抑制活性,其中,谷蛋白多肽抑制率由18.18%(0 d)增加至37.58%(14 d),抑制活性升高。醋浸可改变黑豆各蛋白组分的含量和对应多肽的ACE抑制活性,其中,谷蛋白含量及其多肽ACE抑制活性均有增加。研究结果表明可进一步采用分离纯化技术从谷蛋白多肽中获得高活性降压肽。     

Effect of soy-fortification method on the fermentation characteristics and nutritional quality of fermented maize meal

Studies were conducted to develop an appropriate household/small-scale enterprise level technique for the production of soy-fortified fermented maize dough (or meal) by comparing different treatments, processing methods and fortification levels. The effects of fortification method of the Ghanaian traditional fermented maize dough with raw or heat-treated whole soybeans and full-fat soyflour at 0%, 10% and 20% replacement levels, on the rate of fermentation and product quality were investigated. Sensory characteristics, trypsin inhibitor activity, amino acid pattern, proximate composition and hot paste viscosity were used as the indices of quality. Addition of whole soybeans to maize before milling and fermentation reduced the fermentation time by 60% while increasing the protein content by 24% and 70% respectively for 10% and 20% levels of fortification. A significant improvement was also achieved in the amino acids pattern of the fortified dough. However, raw whole soybeans imparted an undesirable color and beany flavor and an appreciable concentration of trypsin inhibitor activity (TIA) to the dough. Boiling soybeans for 20 min before incorporation into the maize for milling and fermentation was found necessary for desirable flavor and low levels of TIA. Little or no changes in the pasting viscosity characteristics occurred in samples containing boiled soybeans, while the usual method of fortifying maize meal with soy flour was found to severely depress the pasting viscosity characteristics and drastically reduced the acidity of the fermented dough. Based on the findings of the study, the most appropriate technique for the production of soy-fortified high protein fermented maize dough has been suggested to involve incorporation of boiled whole soybeans in soaked maize before milling and fermentation for improved sensory characteristics, enhanced nutritive value and optimal functional properties.     

Oligosaccharins of Black Gram (<Emphasis Type="Bold">Vigna mungo</Emphasis> L.) as Affected by Processing Methods

The oligosaccharide content was determined in 12 different cultivars of black gram. The effect of various treatments such as soaking, cooking, and enzyme treatment on the raffinose family oligosaccharides of dry seeds and flour was studied. Ajugose, a higher oligosaccharide (DP 6) found in trace quantities in seeds, was shown in black gram by HPLC. The percent reduction of raffinose, stachyose, verbascose, and ajugose after soaking for 16 hr was 41.66%, 47.61%, 28.48%, and 26.82%, respectively in Local-I variety and 43.75%, 20.58%, 23.60%, and 15.88%, respectively in Local-II variety. Cooking for 60 min resulted in decrease of 100% for raffinose, 76.19% for stachyose, 36.39% for verbascose, and 60.97% for ajugose in Local-I variety and 100% for raffinose, 55.88% for stachyose, 48.52% for verbascose, and 56.07% for ajugose in Local-II variety. Thin layer chromatographic analysis of 3 hr enzyme-treated samples revealed almost complete hydrolysis of raffinose family of oligosaccharides. Among the different methods employed, enzyme treatment was found to be the most effective for removing α-galactosides in black gram.     

Effect of heat treatments on trypsin/chyomotrypsin inhibitor activity of red gram (Cajanus cajan L.)

The application of dry heat to the seeds and meal was not effective in inactivating the trypsin inhibitory activity (TIA) and chymotrypsin inhibitory activity (CIA). Soaking for 24 hours followed by cooking for 20 min was effective in destroying the TIA and CIA.