In vitro digestibility of Bacillus fermented soya bean

Bacillus fermented legume products include among others dawadawa and soumbala made from African locust bean, and natto and kinema made from soya bean. Bacillus subtilis is the dominant species involved in the fermentation. During Bacillus fermentation for 48 h of autoclaved soya bean the quantity of soluble and dialyzable matter increased from 22% and 6% up to 65% and 40%, respectively. Protein and carbohydrate degradation during fermentation of soya bean with several Bacillus spp. was investigated and appeared to be substantial during the first 18 h of fermentation resulting in the release of high levels of peptides and oligosaccharides. In vitro digestibility was increased from 29% up to 33–43% after Bacillus fermentation for 48 h. It was shown that Bacillus spp. were able to degrade soya bean macromolecules to a large extent resulting in water-soluble low molecular weight compounds. In vitro digestion of Bacillus fermented soya bean using gastrointestinal enzymes only slightly increased the amount of dialyzable matter, which clearly demonstrated the beneficial effect of Bacillus fermentation on food nutrient availability.     

In vitro digestibility of processed and fermented soya bean,cowpea and maize

Tropical legumes, ie soya bean and cowpea, were pre‐treated and subsequently fermented using pure cultures of Rhizopus spp. Impact of soaking, cooking and fermentation of the legumes on their digestibility was determined using an in vitro digestion method. Processing of white maize included, amongst others, natural lactic acid fermentation, cooking and saccharification using barley malt. An in vitro method was standardised to carry out comparative determinations of the dry matter digestibility of cereal and legume food samples as a function of processing conditions, without attempting to exactly mimic gastrointestinal digestion. Using this method based on upper digestive tract digestion, it was observed that digestibility of the legumes increased during cooking and fermentation. Cooking improved the total digestibility of both soya bean and cowpea from 36.5 to 44.8% and from 15.4 to 40.9% respectively. Subsequent fungal fermentation increased total digestibility only by about 3% for both soya bean and cowpea. Digestibility was also influenced by fungal strain and fermentation time. Cooking and subsequent saccharification using malt almost tripled total digestibility of white maize from 25.5 to 63.6%, whereas lactic fermentation of maize had no effect on in vitro dry matter digestibility. Although total digestibility of cooked legumes was only slightly improved by mould fermentation (3% for both soya bean and cowpea), the level of water‐soluble dry matter of food samples increased during fermentation with Rhizopus oryzae from 7.0 up to 27.3% for soya bean and from 4.3 up to 24.1% for cowpea. These fermented products could therefore play a role as sources of easily available nutrients for individuals suffering from digestive disorders. © 2000 Society of Chemical Industry     

Gas producton by Clostridium perfringens as a measure of the fermentability of carbohydrates and processed cereal-legume foods

A new and improved method was developed for the in vitro measurement of gas produced by Clostridium perfringens, in an attempt to determine the fermentability of pure carbohydrates, processed legumes and cereal-legume mixtures. The bacterial strain, inoculum and substrate concentrations and type of carbohydrate all proved to be important factors affecting in vitro gas production by Clostridium perfringens. Increasing glucose concentrations resulted in increased gas production, but only up to 2%, above which it became inhibitive. A 10-fold dilution of the active inoculum reduced the rate of gas production, whilst a 50-fold dilution produced no gas in 24 h. Strain NCTC 8239 was able to ferment a wide range of carbohydrates, with the exception of xylose. Arabinose, ribose and raffinose were, however, only moderately fermented. Native starch was also poorly fermented but, after heating, was fermented with vigorous gas production. Cooked, lactic-fermented cereal-legume composite doughs produced less gas compared to cooked non-fermented doughs. Soaking resulted in decreased fermentability of cowpea and pigeon pea, but the opposite effect was observed with soaked mungbean and soya bean. Fungal fermentation (with Rhizopus oligosporus) into tempe also had varying effects on fermentability, depending on the legume. Fungal-fermented cowpea, groundnut and pigeon pea produced more gas than similarly treated mungbean and soya bean. Steaming these products again had contrasting effects, with cowpea and pigeon pea showing reduced fermentability whilst the fermentability of mungbean and soya bean increased.     

Preparation and characterisation of soya milk enriched with isoflavone aglycone fermented by lactic acid bacteria combined with hydrothermal cooking pretreatment

A fermented soya milk (FSM) enriched with isoflavone aglycone (FSM‐SPIA) was prepared from heated soya protein isolate (SPI)‐isoflavone complex. After 48 h of fermentation, FSM‐SPIA contained higher contents of living bacteria, free amino acids and aglycone compared with the FSM of SPI (FSM‐SPI) and the FSM of SPI‐isoflavone complex (FSM‐Mix). In the in‐vitro digestion experiment, FSM‐SPIA showed higher antioxidant capacity and isoflavones (ISO) bioavailability than FSM‐SPI and FSM‐Mix. This was likely due to the soya milk containing a higher level of amino acid, peptides and the presence of soya bean isoflavone. The improved protein digestibility, the interaction and binding ability between proteins and ISO may affect the properties of the protein and the fermented products. The FSM enriched with isoflavone aglycone can be used as a functional fermented drink, as well as an auxiliary food for menopausal women during a specific pathological period.     

混菌发酵豆豉中异黄酮含量及对小鼠肺癌细胞的抑制作用

选用高产蛋白酶菌株枯草芽孢杆菌D2和β-葡萄糖苷酶产生菌枯草芽孢杆菌U35进行单菌种、混合菌种发酵生产豆豉,测定大豆异黄酮含量及其抗肿瘤能力,分析异黄酮含量和抗肿瘤能力的关系。用HPLC法测定豆豉提取物异黄酮含量,采用MTT比色法检测异黄酮含量对细胞增殖的影响,并在荧光显微镜下观察小鼠肺癌(LLC)细胞形态变化。结果表明,D2U35混菌豆豉苷元型异黄酮含量分别比D2、U35单菌豆豉高101.95μg/mL(2.38倍)和35.48μg/mL(1.25倍),D2U35混菌豆豉对肿瘤细胞的抑制率分别比D2、U35单菌豆豉高15.79%和7.02%,说明混菌发酵不仅提高了苷元型异黄酮含量,还提高了豆豉提取物的抗肿瘤能力。对肿瘤抑制作用,苷元苷型异黄酮>总异黄酮>糖苷型异黄酮。     

Changes in Soya Bean Lipid Profiles during Kinema Production

The influence of processing on soya bean lipids during kinema production was studied. The crude lipid (CL), free fatty acid (FFA) and phytosterol contents of raw beans were 121 g, 6·9 g and 0·8 g kg⁻¹ dry matter, respectively. After soaking and cooking the moisture content of beans increased significantly from 121 to 749 g kg⁻¹, whilst the lipid contents were unchanged. During a 2 day fermentation at 37°C, the lipid contents increased significantly as indicated by capillary column gas chromatography (GC) analysis of petroleum ether extracts of lyophilised samples of unfermented and fermented beans. The fatty acids, palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2), linolenic (C18:3) and arachidic (C20:0) acids were identified. The major fatty acid present in all samples was the essential fatty acid, linoleic acid. All of the aforementioned fatty acids (except arachidic) were liberated during fermentation by microbial lipases, yielding approximately the same proportion of fatty acids found in unfermented beans. The unsaponifiable soya bean lipids identified by GC were campesterol, stigmasterol and β-sitosterol (ratio 1·2:1:3·4). Levels of these increased during fermentation by 50–61%, but remained in approximately the same proportions.     

Fermentation alters antioxidant capacity and polyphenol distribution in selected edible legumes

This study was designed to investigate the influences of fermentation by naturally occurring bacteria on legumes and lactic acid bacteria on antioxidant capacity and polyphenols in both soluble and bound extracts of eight common edible legumes, including black cow gram, mottled cowpea, speckled kidney bean, lentil, small rice bean, small runner bean and two soya beans. Fermentation had varying effects on the antioxidant capacity of soluble and bound extracts in different edible legumes, with fermented mottled cowpea, speckled kidney bean and small rice bean showing increased total antioxidant capacity. In addition, fermentation in general enhanced total phenolic content in all the selected legumes, which could be associated with the biotransformation between soluble phenolics and the release of bound phenolics induced by micro‐organisms involved in the fermentation process. Phenolic compounds, such as catechin, were increased in fermented mottled cowpea. Overall, fermentation could increase the bioavailability of legume polyphenols and fermented legume powders rich in antioxidant polyphenols can be used to develop novel functional foods.     

鹰嘴豆纳豆液态发酵高产蛋白酶的培养基及发酵条件优化

为了提高纳豆中的蛋白酶活力,以纳豆芽孢杆菌为菌种,对鹰嘴豆纳豆液态发酵进行优化。以蛋白酶活力为指标,采用Plackett-Bnrmao法筛选出三个对蛋白酶活力影响最大的因素:装液量、转速和鹰嘴豆粉添加量。通过响应面优化鹰嘴豆纳豆液态发酵的培养基和发酵条件,建立二次回归模型的拟合度良好,对提高蛋白酶活力影响显著(p<0.005),所得最佳培养基为鹰嘴豆粉添加量5.9%,豆粕粉1.0%,葡萄糖0.6%,氯化钠0.5%,最佳发酵条件为:转速250 r/min,装液量76 mL/500 mL,温度37℃,发酵时间48 h。该条件下发酵所得蛋白酶活力达(3558.0±1.5) U/mL,相对于对照培养基的(2491.4±2.8) U/mL提高了42.8%,且纤维蛋白平板法验证的纳豆激酶溶解圈面积提高了108.6%。结果表明,优化后的鹰嘴豆纳豆液态发酵能有效提高蛋白酶活力。     

Chemical and Enzymic Changes During the Fermentation of Bacteria-Free Soya Bean Tempe

Amounts of dry matter, ash, protein, free ammonia, crude lipid, glyceride–glycerol, free fatty acids, free glycerol, glucosamine, protease activity and lipase activity were monitored during the fermentation of bacteria-free tempe made with acidified soya bean cotyledons and Rhizopus oligosporus NRRL 2710 at 30°C. During the phase of mycelial growth (0–32 h) the total dry matter decreased by approximately 10% (w/w), accounted for by losses of crude lipid (3% of initial dry matter), protein/amino acids (0·5%), and unidentified compounds (6·5%). During the phase of mycelial senescence (60–180 h), decrease in dry matter (12% of initial dry matter) was due almost entirely to loss of crude lipid. Lipase activity and the production of free fatty acids occurred from the earliest stages of the fermentation. The production of only small amounts of free glycerol indicates that triglycerides were primarily hydrolysed to partial glycerides and free fatty acids. Protease activity and production of free ammonia were also detected at the earliest stages of the fermentation. During the phase of mycelial senescence, amounts of crude lipid and glycerol decreased in the absence of fungal growth, possibly due to the activity of enzymes released from senescent mycelium.     

豆渣腐乳酿制的食用胶筛选及后发酵中营养品质的变化

为解决豆制品企业鲜豆渣大量堆积腐败变质和低值化利用问题，以纯豆渣为原料、毛霉为发酵菌种进行前发酵，利用食用胶将前发酵后的基料成型再后发酵酿制豆渣腐乳。先通过跟踪检测豆渣腐乳的质构，从瓜尔豆胶、魔芋胶、可得然胶、沙蒿子胶、海藻酸钠、聚丙烯酸钠6种食用胶中筛选适宜的食用胶种类及添加量，再通过跟踪考察在40 ℃、28 ℃、室温条件（25~35 ℃）下后发酵的豆渣腐乳中粗蛋白、可溶性蛋白、氨基酸态氮和总酸含量随发酵时间的变化规律以及挥发性风味物质含量，确定后发酵适宜的温度和时间。结果表明，添加0.1%魔芋胶使豆渣腐乳具有较优质构；3种温度下发酵的豆渣腐乳中粗蛋白、可溶性蛋白、总酸和氨基酸态氮含量均随发酵时间的增加呈现先增大后逐渐趋于平稳的变化趋势，3种温度下酿制的豆渣腐乳的粗蛋白含量相差不大，而40 ℃下发酵的豆渣腐乳中可溶性蛋白和氨基酸态氮的含量最高，分别为5.294和0.63075 g/100 g，总酸变化稳定且含量最低，为8.772 g/100 g，产品所需要的成熟时间最短，为35 d，另外，40 ℃下的酯类有12种，含量为55.10%，种类最多含量最高，产品风味品质更优。     

响应面法优化贝莱斯芽孢杆菌发酵水豆豉的工艺条件

发酵产品的质量与微生物的产酶能力和发酵条件息息相关。为提高水豆豉的发酵品质,采用单因素法结合响应面法对一株高产豆豉纤溶酶的贝莱斯芽孢杆菌发酵水豆豉的条件进行优化,以获取最佳的发酵条件。首先利用单因素法缩小发酵时间、温度和接种量的范围,然后通过响应面法以水豆豉中的氨基酸态氮含量和豆豉纤溶酶活性为指标,确定最优发酵条件为:时间5d,温度35℃,接种量0.01%。最终发酵的水豆豉氨基酸态氮含量为8.95g/kg,豆豉纤溶酶活性为420.05IU/g,与市售相比,豆豉纤溶酶活性升高约400倍。该研究为贝莱斯芽孢杆菌发酵水豆豉提供了理论依据。     

Activation of remaining key enzymes in dried under-fermented cocoa beans and its effect on aroma precursor formation

Incubation-activation of remaining key enzymes in dried under-fermented cocoa beans and its effect on aroma precursor formation has been studied using defatted unfermented and partly fermented cocoa bean powders. Results of the study showed that aspartic endoprotease, carboxypeptidase and invertase were significantly inactivated during fermentation and drying, and the effect of fermentation was significantly lower than that of drying. The enzyme activities remaining in these beans were still sufficient to carry out enzymatic reaction during incubation. Peptide patterns, resulting from incubation of unfermented and partly fermented beans powders, were quite similar to the well-fermented patterns. Meanwhile, free amino acid concentrations of the unfermented beans were significantly increased during the first 4 h of incubation and then remained constant; however, with partly fermented beans, the formation continued and the hydrophobic and total free amino acid concentrations reached the value of well-fermented beans after 24 h of incubation. Reducing sugar concentrations of both unfermented and partly fermented cocoa beans could reach the level of well-fermented beans by incubation.     

Physicochemical and pasting properties of maize flour as a function of the interactive effect of natural-fermentation and roasting

The effect of natural-fermentation and roasting on maize physicochemical and functional properties were evaluated. Natural fermented maize seeds were soaked for variable times (0, 24 and 48 h) and directly decorticated or roasted before milling into flour. Generally during the 24 to 48 h natural fermentation, total sugars (80.3–92.0 g/100 g) and proteins contents (4.0–7.6 g/100 g) decreased while they significantly increased with soaking. Soluble sugars content of the unroasted maize significantly decreased with fermentation while that of roasted maize significantly increased. Reverse observations were made on soluble proteins. The antinutrients (phytates and total polyphenols) contents of the grains as well as the functional properties of their flours were observed to have been significantly changed following fermentation and roasting. In particular the least gelation concentration (6 to 18 g/100 mL), an important reverse index of gelating power significantly increased with fermentation and roasting. As consequence the viscosity of the fermented maize flours were systematically significantly lower than that of the unfermented flour. Generally while the effects of duration of fermentation and roasting on the viscosity were not consistent, the 48 h natural fermented and roasted flour was observed to particularly produce flours of much lower viscosity. This highlighted the positive effect of combining fermentation and roasting to improve the quality of weaning flour made from maize.     

豆渣不同菌种发酵后成分变化的研究

用根霉、毛霉、米曲霉菌分别对一定量的豆渣进行发酵,对发酵前后6个时期豆渣的营养成分、酶活力进行分析,结果表明,发酵后豆渣的品质明显提高。豆渣中氨基酸态氮的含量均升高;豆渣中的可溶性总糖含量也明显提高,脂肪含量有所降低。豆渣中蛋白酶活力及淀粉酶活力在发酵前期为最大值,随着时间的延长逐步降低,且毛霉产蛋白酶能力较强,最大值达到96.4 U/g,而根霉产淀粉酶能力较强,最大值达到13.2 U/g。     

植物乳杆菌蚕豆发酵饮料的制备与抗氧化性研究

采用直投式植物乳杆菌作为发酵剂对蚕豆饮料的发酵工艺条件进行优化。以酸度为指标,通过单因素和响应面试验,确定最佳发酵工艺为:接种量0.6%,发酵时间40 h,发酵温度37℃。在此条件下,蚕豆发酵饮料的酸度为15.25%。添加8%的白砂糖后,蚕豆发酵饮料酸甜可口,风味良好。对发酵前后蚕豆饮料的抗氧化性研究表明,发酵后饮料的OH·清除率、DPPH·清除率以及还原力高于发酵前,但是均低于50μg/mL的VC。     

一株强化发酵甜瓣子的乳酸片球菌特性及应用效果评价

甜瓣子是以蚕豆制曲后加盐水发酵而成的,是郫县豆瓣风味形成的关键阶段。筛选适用于强化甜瓣子发酵的专用乳酸菌,以期应用于强化甜瓣子发酵。以甜瓣子为原料筛选生长速度快、产酸能力强的高效乳酸菌,研究其生长特性。利用筛选得到的高效乳酸菌制备菌剂并用于强化甜瓣子发酵,分析甜瓣子品质。该研究筛选得到1株乳酸片球菌ND1,37℃培养6 h、OD610达1.375,培养24 h发酵液中乳酸含量达到1.296 g/100 g。ND1在4~50℃条件生长良好,高温更利于其生长,在37~45℃生长速度最快;能耐受10%的盐,在盐含量(质量分数)为0%~8%的条件生长良好;在pH 3.5~6生长速度快。利用菌株ND1发酵得到的乳酸菌剂活菌数可达1.07×10^12CFU/g,利用该菌剂发酵甜瓣子,可有效提高甜瓣子中有机酸(尤其是乙酸、苹果酸、乳酸)含量,强化甜瓣子风味。该研究筛选的乳酸片球菌ND1具有良好的温度、酸度、盐度适应性,能改善甜瓣子中有机酸含量,有望被用作强化甜瓣子发酵增香的乳酸菌,改善郫县豆瓣品质。     

Soya-yoghurt starter culture development from fermented tropical vegetables

The development of soya-yoghurt starter culture from fermented tropical vegetables was initiated. Soya milk fortified with 10 g litre^?1 sucrose was sterilised (121°C for 15 min) and inoculated with the exudate of fermented tropical vegetables. Acid production in the soya milk medium during incubation at 42°C for 5 h was evaluated and compared with cows' milk based cultures. Aroma of the soya milk based and cows' milk based cultures was also compared. Cultures derived from fermented cassava and corn separately reduced soya milk pH from 6′8 to 43 and 45, and significantly greater culture activity was observed in soya milk than in cows' milk. The culture from corn produced the most acceptable yoghurt-like aroma in soya milk while that from African oil bean seed produced the least acceptable aroma. The consumer-acceptable mild buttermilk-like aroma of yoghurt was not produced in soya milk or cows' milk by the cultures evaluated.     

The nutritional quality of two types of fish silage for broiler chickens

Fish waste was ensiled either by acidification with formic acid or by fermentation with a bacterial starter culture and molasses. The resulting liquids were mixed with wheat bran (85:15 w/w liquid: bran) and dried (70°C) to produce acid silage meal (ASM) and fermented silage meal (FSM). ASM and FSM were incorporated into wheat-based diets at 25, 50 and 100 g kg^?1 at the expense of soya bean meal. There were two control diets, one which contained soya bean meal as the predominant protein supplement and a second in which fish meal (50 g kg^?1) was added at the expense of some of the soya bean meal. Starter diets (13.25 MJ ME kg^?1, 12 g kg^?1 lysine) were fed from 1-day-old to 21-days-old and finisher diets (13.25 MJ ME kg^?1, 9.5 g kg^?1 lysine) were fed from 22 to 42-days-old to six replicates each of five birds. Birds were reared in raised-wire cages, and feed intake, liveweight and mortality were recorded. There were no significant effects of dietary inclusion of either ASM and FSM on the performance of broiler chickens relative to those fed on control diets. FSM contained less crude protein and amino acids than ASM. The recovery of amino acids relative to the total crude protein content from FSM was only 78.7%, presumably as a result of formation of Maillard reaction products during drying.     

芸豆酵素发酵过程中组分及抗氧化功能研究

以紫花芸豆为原料制备芸豆酵素,探究其发酵过程中pH、总酸、还原糖、可溶性固形物、总酚、黄酮含量的变化规律,并分析各成分与抗氧化活性参数（还原力、ABTS+自由基清除率）的相关性。结果表明,芸豆酵素发酵过程中pH持续降低后趋于平缓趋势,总酸变化规律与之相反;还原糖含量由发酵初期小幅度上升至11.2 mg/mL,随之不断下降并于发酵48 h达到最低值3.55 mg/mL;可溶性固形物含量由17.07%持续降低至6.01%;总酚含量总体呈现上升趋势,仅在发酵32 h有所下降,并于发酵结束达到最大值367.92 mg/mL;黄酮含量呈现持续升高趋势并于发酵48 h达到92.24 μg/mL后趋于稳定,芸豆酵素的抗氧化能力（还原力、ABTS+自由基清除率）总体呈现持续增长趋势并于发酵后期达稳定状态,分别于发酵56 h时达到最大值（0.88 μmol/L、88.12%）。功能成分与抗氧化能力参数相关性表明,总酚、黄酮与还原力和ABTS+自由基清除能力具有显著的正相关性（P<0.05）。     

Effect of fermentation on the thiamin, riboflavin and niacin contents of melon seed (Citrullus vulgaris) and African oil bean seed (Pentaclethra macrophylla)

An automated thiochrome method and high performance liquid chromatography (HPLC) with fluorescence detection were used to determine thiamin and riboflavin, respectively, in unfermented, and fermented melon seeds (Citrullus vulgaris) and African oil bean seeds (Pentaclethra macrophylla). Niacin was determined microbiologically. In all the methods used, fermentation significantly increased the content of thiamin, riboflavin and niacin in African oil bean seeds and thiamin and riboflavin in melon seeds. There was no change in the niacin content of melon seeds.