Effect of soaking,germination, cooking and fermentation on antinutritional factors in cowpeas

The present work deals with the study of efficacy of some treatments, namely soaking (in water and bicarbonate solution), ordinary and pressure cooking, germination and fermentation in reducing or removal of antinutritional factors usually present in cowpeas (protease inhibitors, tannins, phytic acid and flatus-producing oligosaccharides (raffinose and stachyose). The results showed that long-time soaking (16 h) in bicarbonate solution caused remarkable reduction in the antinutritional factors. Pressure cooking was more effective than ordinary. Cooking pregerminated cowpeas was most effective. Fermentation completely removed trypsin inhibitor, oligosaccharides and reduced remarkably phytic acid. However, tannins noticeably increased.     

Nutrients and antinutritional factors in faba beans as affected by processing

 The influence on the nutrients content (soluble sugars, starch, dietary fibre and calcium) and antinutritional factors (α-galactosides and phytic acid) of faba beans (Vicia faba, L. major) of soaking in different solutions (distilled water, citric acid, and sodium bicarbonate solutions), cooking the presoaked seeds, dry-heating and germination have been studied. Soaking brought about a decrease in starch, sucrose, fructose, α-galactoside, dietary fibre and calcium content. Glucose was detected in soaked faba beans and soaking did not modify the phytic acid content. Cooking the presoaked faba beans produced a slight decrease in starch, and caused a general drop in α-galactosides, dietary fibre, calcium and phytic acid, with the exception of seeds presoaked in sodium bicarbonate in which cooking did not cause any appreciable changes in comparison with the unprocessed faba beans. Germination caused a sharp reduction in α-galactoside and phytic acid content after 6 days, whilst starch and dietary fibre decreased slightly. Calcium, however, enjoyed a slight increment during germination which was related to the decrease in the content of hemicellulose and phytic acid. Dry-heating caused a noticeable reduction in all the nutrients and antinutritional factors investigated. Of all the treatments studied, germination appears to be the best processing method to obtain nutritive faba bean flour, since it caused a minor decrease in starch content (15% loss), the largest α-galactoside and phytic acid removal (94% and 45%, respectively) and provided an appreciable amount of dietary fibre. Received: 21 December 1997 / Revised version: 19 February 1998     

Content of antinutritional factors and HCl-extractability of minerals from white bean (Phaseolus vulgaris) cultivars: Influence of soaking and/or cooking

White bean seeds were subjected to soaking in distilled water for 1, 2 and 3 days. In order to perform complete processing, the seeds were cooked until soft. Effects of soaking and/or cooking of white bean seeds on antinutritional factors, mineral contents and HCl-extractability were studied. Phytic acid and polyphenol contents of all cultivars were reduced. Soaking alone and soaking, followed by cooking, reduced mineral contents of the cultivars, but HCl-extractability was significantly (P ? 0.01) improved to varying extents, depending on cultivar type. Soaking and/or cooking treatment was thus found to be an effective technique and caused further improvement in the availability of both major and trace minerals in white bean.     

Effects of soaking, germination and fermentation on phytic acid, total and in vitro soluble zinc in brown rice

Rice is an important staple food in Asian countries. In rural areas it is also a major source of micronutrients. Unfortunately, the bioavailability of minerals, e.g. zinc from rice, is low because it is present as an insoluble complex with food components such as phytic acid. We investigated the effects of soaking, germination and fermentation with an aim to reduce the content of phytic acid, while maintaining sufficient levels of zinc, in the expectation of increasing its bioavailability. Fermentation treatments were most effective in decreasing phytic acid (56–96% removal), followed by soaking at 10 °C after preheating (42–59%). Steeping of intact kernels for 24 h at 25 °C had the least effect on phytic acid removal (<20%). With increased germination periods at 30 °C, phytic acid removal progressed from 4% to 60%. Most wet processing procedures, except soaking after wet preheating, caused a loss of dry mass and zinc (1–20%). In vitro solubility, as a percentage of total zinc in soaked rice, was significantly higher than in untreated brown rice while, in steeped brown rice, it was lower (p < 0.05). Fermentation and germination did not have significant effects on the solubility of zinc. The expected improvement due to lower phytic acid levels was not confirmed by increasing levels of in vitro soluble zinc. This may result from zinc complexation to other food components.     

The effect of popping,soaking, boiling and roasting processes on antinutritional factors in chickpeas and red kidney beans

This study was conducted to determine the effect that a popping head (like a rice cake machine), a low-shear and low-water processing technology, has on the concentration of antinutritional factors in chickpeas and red kidney beans. Seeds were popped under several parameters (popping time, sample format and equipment type) and analysed against soaking (1:5 w/v in reverse osmosis water for 24 h), roasting (100 g at 180 °C for 20 min) and boiling (1:5 w/v in reverse osmosis water at 100 ± 1 °C for 1 h) processes. Popping and roasting significantly reduced phytic acid content in chickpeas (6%–22%) and red kidney beans (16%–39%). In contrast, phytic acid content after soaking and boiling was not significantly different to raw seeds. Condensed tannins were significantly reduced in red kidney beans after soaking (74%), boiling (100%) and 4 s popping (28%–42%) treatments and increased in both pulses after roasting (137%) and 8 s popping (21%–47%). Further analysis showed that the soluble phenolic content increased with popping, but total and bound phenolic content was reduced. These results demonstrate that the high temperatures and pressures applied during the popping process effectively reduce antinutritional factors in pulses, compared to conventional processing methods.     

Changes in phenolic compounds in lentils (Lens culinaris) during germination and fermentation

 Germination and fermentation have been proposed to improve the nutritive value of legumes. This paper reports the changes that occur in phenolic compounds in lentils (Lens culinaris var. vulgaris) during germination and fermentation. Levels of low-molecular-weight phenolic compounds (benzoic acids and aldehydes, hydroxycinnamic acids and derivatives, flavan-3-ols and procyanidins) were determined. Germination did not appreciably vary the content of phenolic compounds, although important structural changes in procyanidin-type compounds were observed. Fermentation led to a general increase in the content of phenolic compounds. Gentisic acid, p-hydroxyphenylpropionic acid, tryptophol and three other unknown compounds were detected in fermented lentils, but not in raw lentils. The influence of these changes on the potential antinutritional effects associated with phenolic compounds in legumes, as well as on the antioxidant properties attributed to these compounds is discussed. Received: 16 December 1996 / Revised version: 6 March 1997     

Effect of Processing on Anti-nutritional Factors of Red Kidney Bean (Phaseolus vulgaris) Grains

The effect of different processing methods (soaking in water or solutions of sodium bicarbonate, citric acid, soaking plus cooking, and germination) on anti-nutritional factors (phytic acid, total polyphenols, tannins, and hydrocyanic acid) of red kidney bean was studied. The anti-nutritional factors were reduced significantly (P < 0.001) with processing techniques. Cyanide contents were most effectively (25%) reduced by cooking after soaking in sodium bicarbonate solution, followed by germination. The most drastic effect was noted on tannin contents. Cooking after soaking in either citric acid or sodium bicarbonate solutions almost eliminated it. However, simple soaking in water did not result in any reduction in tannin contents. Reduction in total polyphenols was 78.7% with cooking after soaking in sodium bicarbonate solution. Phytic acid contents were reduced only with germination treatment (42.6%), while the other treatments did not bring about any large reduction.     

Influence of fermentation on the nutritional value of two varieties of<Emphasis Type="Italic"> Vigna sinensis</Emphasis>

Cowpeas ( Vigna sinensis) are a good source of protein and energy. They are widely consumed all over the world, mainly in rural populations, and satisfy a considerable proportion of the protein requirements. However, like other pulses, cowpeas contain several antinutritional factors, which limit their consumption and affect the digestibility and bioavailability of nutrients. Fermentation seems to enhance the nutritive value of legumes. The present work studies the effect of natural fermentation and subsequent cooking process of two varieties of Vigna sinensis on the content of protein, minerals, ash, fat, soluble and insoluble dietary fibre, -galactosides, inositol phosphates, trypsin inhibitor activity (TIA), water-soluble vitamins (thiamin and riboflavin) and protein quality parameters, in vivo digestibility and PER (protein efficiency ratio). The processes applied caused a significant increase of vitamin B_2, and significant reductions in the contents of TIA (40%) and phytates (100%), main antinutritional factors present in cowpeas. Likewise, the soluble fibre and -galactosides compounds that produce flatulence diminished (67 and 100%, respectively). Protein digestibility for Orituco variety was adequate among legumes (82.8–88.4%), although only Vigna sinensis var. Orituco showed an acceptable PER value (1.63).     

Effect of alkaline pretreatment and cooking on protein fractions of a high-tannin sorghum cultivar

A high-tannin sorghum cultivar (Karamaka) was used to study the effect of soaking in distilled water or 0.05%, 0.10% and 0.20% NaOH for 8 h, and soaking in distilled water or NaOH followed by cooking, on proximate composition, tannin content and protein fractions. Results showed that soaking the sorghum grains in water or NaOH for 8 h caused a slight increase in crude protein, whilst the tannin content significantly (p ? 0.05) decreased. The highest drop in tannin content was observed after soaking sorghum in 0.20% NaOH for 8 h at ambient temperature. Combining soaking and cooking further lowered the tannin content of sorghum, with a maximum reduction of 83.9%. Soaking in NaOH and cooking caused significant (p ? 0.05) increases in the albumin and globulin fractions, accompanied by a significant reduction in the glutelin fraction. This readjustment of sorghum protein fractions would indicate improvement in the quality of sorghum proteins.     

Polyphenols and tannins in Indian pulses: Effect of soaking,germination and pressure cooking

Polyphenols and tannins have implications for health and nutrition. There is limited information on their content in pulses, raw or post-processing. We estimated the concentrations of polyphenols and tannins in different cultivars of four pulses commonly consumed in India – Phaseolus aureus, Cajanus cajan, Lens esculenta and Cicer arietinum – and examined the effects of domestic processing. Means and standard deviations were calculated and results were analyzed by ANOVA. There were significant differences (P < 0.001) in the polyphenol and tannin contents of cultivars of the same pulse, with the exception of the tannin contents of pressure-cooked red gram cultivars (P = 0.3103). Processing reduced the concentrations of polyphenols by 19–59% and of tannins by 22–59%. A trend was observed in the degree to which processing reduced polyphenol and tannin contents (germination > pressure-cooking > soaking). Soaking, germination and pressure-cooking proved to be effective household strategies to reduce the levels of polyphenols and tannins in pulse-based foods, thereby enhancing the bioavailability of pulse protein. There is a need to determine the extent to which the remaining polyphenols and tannins are rendered unavailable by these processing techniques.     

Evaluation of mustard (Brassica juncea) protein isolate prepared by steam injection heating for reduction of antinutritional factors

A process for the preparation of mustard protein isolate, comprising steps such as dispersion of defatted meal in 0.1 mol/l NaCl solution, incubation, extraction at alkaline pH, followed by treatment of the protein solution with activated carbon was developed. The protein, coagulated by steam injection, was subjected to separation by centrifugation, washing and spray drying. The parameters evaluated were protein yield, purity, presence of antinutritional factors and nutritional quality of proteins. The protein yield was 58-60%. The purity of the protein isolate was 95%. The hydrolysed products of glocosinolates like isothiocyanates and oxazolidine thione levels, phenolics and phytic acid levels were low in the protein isolate. The in vitro digestibility of the protein isolate was 92.4% compared to 80.6% of the meal. Chemical score of the meal and protein isolate were similar; isoleucine was the first limiting amino acid. The calculated nutritional indices, essential amino acid index, biological value, nutritional index and C-PER of protein isolate were higher compared to meal. The protein quality as indicated by amino acid profile and PDCAAS scores for 10-12-years old and adults were 100.     

半干米粉的发酵工艺优化及蒸煮品质、质构特性分析

以半干米粉的吐浆率和质构特性作为评价指标,探讨自然发酵和接种发酵对半干米粉蒸煮品质和质构特性的影响,并在单因素实验基础上应用响应面法优化发酵工艺,得出较优的发酵工艺条件,并对其进行蒸煮品质和质构特性分析。结果表明：半干米粉在(25±2)℃的温度下自然发酵3 d时蒸煮品质和质构特性的表现是能接受的,而接种发酵在发酵温度35℃、菌种添加量106 CFU/g时仅发酵48 h蒸煮品质和质构特性就达到最佳;响应面优化接种发酵工艺的参数为发酵温度35℃、发酵时间52 h、菌种添加量106 CFU/g,在此条件下半干米粉吐浆率为(4.32±0.05)%。本实验获得的半干米粉与不发酵的样品对比可知,硬度提高了55.61%、黏性降低了92.88%、弹性提高了4.34%、咀嚼性提高了125.89%、内聚性提高了6.46%、回复性提高了8.46%、吐浆率降低了50%。     

Effect of soaking, germination, autoclaving and cooking on chemical and biological value of guar compared with faba bean

Raw, soaked, germinated, autoclaved and cooked both of guar and faba bean were chemically and biologically evaluated. Crude protein, crude fiber and ash contents of guar and faba bean decreased as a result of all treatments with the exception of protein content in both germinated guar and faba bean. A slight decrease in lipid content was noticed during germination, while there were no changes in lipids after soaking, autoclaving and cooking. Protein content of guar was higher than of faba bean, and showed higher values for all amino acids than faba bean protein except for lysine and tryptophan. Germination caused a slight increase in total essential amino acids, while soaking caused a slight decrease in both of guar and faba bean. There was a slight decrease in the mineral contents by the heat processes with the exception of Mg and Mn for guar and Na, Mn for faba bean due to the cooking process. Germinated guar and faba bean showed noticeable decrease in Na, K, Cu, Mn and Mg and a slight increase in Fe and Zn than the raw materials. Germination was more effective in reducing phytic acid than heat treatment, and therefore it improves the nutritional quality of both guar and faba bean. Protein efficiency ratio (PER), true digestibility (DT) and biological value (BV) were estimated in all treatments under study using rat bioassay procedures. Data revealed pronounced improvements of the nutritive value as a result of all processes under study especially germination being the most effective.     

Effect of soaking and phytase treatment on phytic acid,calcium, iron and zinc in rice fractions

With the aim to maximise phytic acid removal and minimise losses of dry matter and minerals (Ca, Fe, Zn) in rice, three products (whole kernels and flour milled from white and brown rice; and bran, all from the same batch of variety Kenjian 90-31) were soaked in demineralized water at 10 °C (SDW), NaAc buffer of pH 3.5 at 10 °C (SAB), and 500 U L⁻¹ phytase of pH 5.5 at 50 °C (SPS). In whole kernels and flour of white rice, phytic acid removal was 100% by all treatments; losses of dry matter, Ca, Fe, and Zn were 2–5%, 12–63%, 9–10%, and apparent gain of 63–72%, respectively. In whole brown rice, SAB removed 75% phytic acid, and SPS 100% from flour; dry matter, Ca, Fe, and Zn losses were 1–16%, 26–56%, 39–45%, and 23–24%. In rice bran, SPS removed 92% phytic acid, and SAB 50%; dry matter, Ca, Zn, and Fe losses were 20%, 48%, 63%, and apparent gain of 5%, respectively.     

Jatropha platyphylla, a new non-toxic Jatropha species: Physical properties and chemical constituents including toxic and antinutritional factors of seeds

Local communities in Mexico consume Jatropha platyphylla seeds after roasting. The kernels of J. platyphylla contained ca. 60% oil and were free of phorbol esters. The kernel meal of this Jatropha species contained trypsin inhibitor, lectins and phytate. However, trypsin inhibitor and lectins are heat labile so this explains why the local people can eat roasted seeds without ill effects. Heat-treated J. platyphylla kernel meal (JPKM) was free of trypsin inhibitor and lectin activities. Crude protein content of JPKM was 75%. Heated JPKM and soybean meal were included in a standard diet (crude protein 36%) for Nile tilapia (Oreochromis niloticus) to replace 50% of the fish meal protein. The growth of fish in all the three groups was statistically similar and the blood biochemical parameters that serve as biomarkers for toxicity were within the normal ranges. This is the first study that confirms the non-toxic nature of J. platyphylla.     

不同浸泡条件对薄膜包装材料总迁移量检测结果的影响

薄膜普遍用作食品直接接触包装材料。薄膜包装材料在使用过程中要与食品直接接触较长时间。如果生产的薄膜材料所用原材料不合格,生产工艺不合理,薄膜材料中的某些化学成份就可能会很快渗透或溶入到食品中,尤其在遇到高温、高油、醋等物质可直接转移到食品中,造成食品的化学性污染^[1]。我国食品卫生法明确规定,对食品包装材料必须进行卫生检测^［2］。总迁移量是国家标准中检测食品包装材料卫生标准分析方法中的重要指标,指的是从食品接触材料及制品中迁移到与之接触的食品模拟物中的所有非挥发性物质的总量^[3]。本文以本公司使用的左旋肉碱胶薄膜包装材料不同浸泡方法与浸泡条件的总迁移量进行探讨。     

桃色顶孢霉发酵液对大豆的促生及对抗氧化酶活性的影响

采用管碟法和种子萌发法研究桃色顶孢霉对茄病镰刀菌Fusarium solanae的拮抗作用以及对大豆的促生作用,并采用愈创木酚法、紫外吸收法、氮蓝四唑光化还原法研究了顶孢霉发酵液对POD、CAT、SOD三种抗氧化酶活性的影响。结果表明：顶孢霉发酵液对镰刀菌菌丝生长有明显抑制作用,菌丝变稀疏。大豆种子经不同浓度桃色顶孢霉发酵液处理后,萌发率及种子酶活性均产生变化。不同浓度的发酵液对种子萌发促进作用不同,当发酵液浓度为10％时,胚根长、胚芽长、胚根鲜重和胚芽鲜重均达到最高值,分别为2．91cm、0．037g、4．07cm 和0．1666g,与对照相比分别提高了49．37％、63．24％、30．54％和45．80％。当处理种子的发酵液浓度为60％时,种子萌发率最高为83．67％,与对照相比提高了23．90％;POD、CAT和 SOD 酶活性最强,分别为683U、160．6U 和301U,与对照相比分别提高73．50％、43．78％和76．74％。初步证实了桃色顶孢霉发酵液中含有能够促进大豆种子萌发及抗氧化酶活性升高的物质。     

Effect of ionizing radiation on antinutritional features of velvet bean seeds (Mucuna pruriens)

Impact of gamma irradiation on the antinutritional constituents of seeds of Mucuna pruriens was assessed on exposing to doses of 2.5, 5.0, 7.5, 10, 15 and 30 kGy. Except for 2.5 kGy, the rest showed significant dose-dependent increase in phenolics. Tannin concentration did not differ significantly up to 7.5 kGy, while it significantly increased at higher doses. Excluding 2.5 kGy, the rest of the treatments showed significant decreases in the phytic acid and complete degradation was attained at 15 and 30 kGy. The l-DOPA concentration showed a dose-dependent decline. A trace amount of hemagglutination activity was seen on human erythrocytes in raw seeds, which was completely absent on irradiation (>5 kGy). Concentration of Polonium-210, a natural radionuclide falls within the admissible limits for consumption. As Mucuna seeds serve as food, feed or as pharmaceuticals, it may be necessary to set the ionizing radiation to a specific dose to retain optimum levels or to eliminate phenolics, tannins, phytic acid and L-DOPA. As irradiation is a physical and cold process, it may be ideal and emerge as an important technique to improve the nutritional or pharmaceutical quality of Mucuna seeds and its products.     

The in vitro protein digestibility,microbiological quality and gelatinization behaviour of macaroni as affected by cowpea flour addition

Cowpeas were germinated, fermented, cooked, ground to flour and added to standard durum wheat semolina at 20% (w/w) level for macaroni production. Macaroni samples were analysed for in vitro protein digestibility, microbial count (total bacteria, mould and yeast) and gelatinization behaviour over a 6-month storage period at room temperature (<25 °C). Starch gelatinization behaviour of the samples was analysed using differential scanning calorimetry. Supplementing semolina with cowpea flour did not have a significant affect on in vitro protein digestibilities or aerobic plate counts of macaroni samples (p < 0.05). There was a small but significant increase in mold and yeast counts after 6 months of storage in cowpea treated samples. Two endothermic peaks were observed with significant differences in ΔH values of control and cowpea treated macaroni samples. The transition peak (T_p) temperatures were in the range of 66.9–67.9 and 86.9–100.4 °C for the first and second peaks, respectively. The transition enthalpies (ΔH) were in the range 2.41–4.21 and 1.71–3.86 J/g for the first and second peaks, respectively.     

Effect of fermentation and cooking on protein quality of maize (Zea mays L.) cultivars

Maize like other cereals shows qualitative and quantitative deficiency in protein content. Efforts were made to correct this by fortification, supplementation and fermentation. Two maize cultivars, Hudeiba 1 and Mugtama 45, were used to study the effect of fermentation followed by cooking on their protein quality. Maize flour was fermented for 32 h; samples were withdrawn at 8 h intervals. Results indicated that the proteins fractions albumins plus globulins were significantly (P < 0.05) increased in the fermented doughs. This is an indication of improvement in the protein quality of maize. Cooking resulted in significant (P < 0.05) changes in protein solubility. The essential amino acids particularly lysine increased from 1.82 to 2.06 and from 1.88 to 2.60 g/100 g (i.e. an increase of 11.6% and 27.7%) for Hudeiba 1 and Mugtama 45, respectively. The in vitro protein digestibility of cooked samples decreased significantly (P < 0.05); however, the negative effects of cooking were lower than those of unfermented cooked samples.