Extraction and physicochemical properties of soya bean protein and oil by a new reverse micelle system compared with other extraction methods

Reverse micelle extraction is a novel technology for the separation of plant components such as proteins and oil. In this study, sodium bis(2‐ethylhexyl) sulphosuccinate (AOT) reverse micelle system and AOT/Tween 85 reverse micelle system were used to extract soya bean protein and oil from soya bean flour. The physicochemical properties of the protein and oil extracted were investigated and compared with traditional extraction methods. The results showed that the efficiency of forward extraction of soya bean protein using an AOT/Tween 85 reverse micelle system was superior to that using an AOT reverse micelle system at the optimal extraction conditions. In addition, soya bean proteins extracted using reverse micelle extraction had no unordered structure under Fourier transform infrared spectroscopy. The acid and peroxide values of oil products from two reverse micelle extractions were lower than that from immersion. The results indicated that AOT/Tween 85 reverse micelle system is effective in extracting soya bean protein and oil.     

Total inactivation of lipoxygenase in whole soya bean by pulsed light and the effect of pulsed light on the chemical properties of soya milk produced from the treated soya beans

The inactivation of lipoxygenase (LOX) in the whole soya bean prevents lipid oxidation that produces an off‐flavour of soya food. The inactivation of lipoxygenase in the whole soya bean by pulsed light (PL) was examined with three distances (5, 7 and 9 cm) from the PL strobe and for different durations. Soya bean was treated with PL with and without ice surrounding the soya bean sample tray for limiting the rise in sample temperature. Results show that without ice surrounding the sample tray, the lowest LOX residual activity was 4.7%, 0.4% and 0.0% for 80‐s duration at 5 cm distance from the PL strobe, 110 s at 7 cm from the strobe and 150 s at 9 cm from the strobe, respectively; the soya bean temperature after treatment was 109.6, 116.3 and 114.8 °C, respectively. The instantaneous temperatures of the soya bean core measured during PL operating were above 100 °C. The lipoxygenase band was disappeared after longest PL treatments of each distance compared with the LOX band control as assessed by electrophoresis. The pulsed light had no negative effect on peroxide value of produced soya milk. However, PL reduced significantly the total solid amount and changed the colour of the produced soya milk. The residual activity with sample cooling by ice during treatment was 79.0%, 98.8% and 95.7%, with sample temperatures of 81.7, 91.2 and 66.9 °C, respectively. This study indicates that PL illumination could fully inactivate LOX in whole soya beans, with the photo‐thermal effect of PL as the main factor responsible for the inactivation of LOX.     

黑豆脂肪酸成分的GC/MS分析

采用石油醚抽提黑豆油,用氢氧化钾-甲醇法脂化后进行GC/MS分析,确认出14种脂肪酸,所鉴定组分占总峰面积的99.05%,其中脂肪酸主要成分相对含量:棕榈酸(16.40%),亚油酸(47.59%),油酸(14.19%),亚麻酸(6.36%),硬脂酸(10.10%)。     

Physicochemical properties and storage stability of spray‐dried soya bean sprout extract

Amylase is a very important enzyme due to its wide food applications. To preserve amylase activity in soya bean sprout extract (SSE), SSEs were spray‐dried with 10% maltodextrin and 0–3% alginic acids, and their physicochemical properties and storage stability were compared with freeze‐dried one. SSE exhibited maximum amylase activity at pH 7.0 and 60 °C, with the most active substrate specificity towards soluble starch. Spray‐dried SSEs exhibited higher water solubility index (WSI) and in vitro relative amylase activity but lower water vapour sorption (WVS) and smaller particle size than freeze‐dried SSE. For spray‐dried SSEs, particle size, WSI and in vitro relative amylase activity increased while WVS decreased with increasing % alginic acid. This study demonstrated that spray drying of SSE, especially with 10% maltodextrin and 2% alginic acid, was effective in keeping amylase active and stable during 7‐week storage at room temperature (25 °C).     

基于脂肪酸组成结合主成分分析识别不同比例大豆油和菜籽油调配的调和油

结合脂肪酸组成和化学计量学方法,对大豆油、菜籽油及其不同比例的二元调和油的识别进行基础研究,并分析不同比例调和油中脂肪酸含量的变化。结果表明在大豆油和菜籽油中,共检出脂肪酸组分17种,主要以油酸、亚油酸、棕榈酸和亚麻酸为主。在以不同比例低芥酸菜籽油和大豆油调配的调和油中,脂肪酸含量随调和比例的改变而呈现一定趋势的增加或减小。结合脂肪酸组成,对所有的139个样品进行了主成分分析(PCA),结果表明大豆油和菜籽油可以互相实现区分,不同比例的调和油样品分布在调配的溯源样品之间,基本按照比例关系分布成一条直线。研究通过对菜籽油、大豆油及其不同比例调配的调和油的脂肪酸组成进行了定量分析,分析了它们之间脂肪酸组成的变化,并结合化学计量学手段进行一些识别分析,为规范调和油的生产和保障公平有序的调和油市场提供参考。     

大豆油活性白土脱色影响因素

研究了大豆油脱色工艺中脱色温度、脱色时间及活性白土添加量对脱色效果的影响,并分析了活性白土水分含量、比表面积对其吸附效果的影响。结果表明：以精炼小包装巴西一级大豆油为例,实验室最佳脱色工艺条件为脱色时间30 min、脱色温度120 ℃、活性白土添加量0.9%、活性白土水分含量8%、活性白土比表面积180 m2/g;在最佳脱色条件下,脱色油吸光度为0.60,脱色油品质较好,进一步降低了脱臭能耗。     

Textural modification of soya bean/corn extrudates as affected by moisture content, screw speed and soya bean concentration

A Clextral BP‐10 (type BC45) co‐rotating twin‐screw extruder was used for texture modification of extrudates. Dry materials were mixed in a mixer for 15 min at low speed before extrusion. Moisture content 21–23% and addition of soya bean flour (0–40%) showed significant influences on the texture of the extrudates. Addition of soya bean flour in the range from 0 to 40% increased the diametrical expansion ratio (P < 0.01), decreased the hardness (P < 0.01) and modifies specific volume and chewing behaviours of the extrudates. Increasing moisture content in the range from 21 to 23%, however, significantly decreased specific volume (P < 0.01), and increases hardness (P < 0.01) of the extrudates. The hardness and crispness of the extrudates at fracturability of 110 g were graded higher than 6.0 by 30 and 27 of 34 consumer panelists, respectively. Consumer purchase intent showed the highest score of 5.5 in a 9‐point hedonic scale when sample fracturability was at 110 g.     

Preparation and characterisation of glyceollin‐enriched soya bean protein using solid‐state fermentation

Glyceollins, stress‐induced phytoalexins from parent soya bean isoflavones, were elicited with Aspergillus oryzae. This solid‐state fermentation facilitated the conversion of isoflavone glycosides into aglycones and glyceollins, which could mainly enrich in soya bean protein isolate (SPI) during protein preparation due to protein–polyphenol interactions. Glyceollin‐enriched SPI exhibited less flavour volatiles, higher solubility, lower whiteness and higher antioxidant activity than unfermented SPI. Fermented SPI was more easily to be digested during in vitro pepsin–trypsin digestion. This may be attributed to partial degradation of protein, especially α′ and α subunits of β‐conglycinin and acidic subunit of glycinin. The antioxidant activity of digestive products derived from fermented SPI was obviously enhanced with increasing digestion time due to simultaneous release of antioxidant peptides and glyceollins involved in the interior of protein molecule. These results suggest an effective technique for producing a nutrient‐enhanced SPI as novel functional ingredients applied in food industry.     

Response of intestinal proteinase activities to the feeding of isolated winged bean (Psophocarpus tetragonolobus) and soya bean (Glycine max) trypsin inhibitors in rats

The antinutritional activities of trypsin inhibitors (TIs) were compared between winged beans (Psophocarpus tetragonolobus) and soya beans (Glycine max). The inhibitors of the two beans were isolated by trypsin‐bound Sepharose 4B, and 50 mg of lyophilised powders were intubated intragastrically into 24 h fasted rats. The activities of trypsin and chymotrypsin were compared after 30, 60 and 180 min in the washings of the upper, middle and lower parts of the small intestine. The elution profiles of TI and non‐TI compounds in the affinity chromatography were similar in the two beans, and the antitryptic activities were concentrated 5.5 and 6.2 times (based on specific activity) for winged beans and soya beans respectively. Regardless of the TI fed to rats, trypsin activity in the upper intestine was suppressed to almost undetectable levels at 30 and 60 min after intubation. The activities in the middle and lower intestines were also substantially lowered when rats were fed winged bean TI, and significant differences were detected at 30 and 60 min after intubation when compared with rats fed soya bean TI. However, at 180 min after feeding, no differences were found in the trypsin activity in any gut segments. Similar inhibitory properties of isolated TIs were observed in chymotrypsin activities in the small intestine. The results suggest that winged bean TI may have greater inhibitory activity on the intestinal proteinase compared with soya bean TI. © 2001 Society of Chemical Industry     

Formation of lysinoalanine following alkaline processing of soya bean meal in relation to the degradability of protein in the rumen

Effects of sodium hydroxide (NaOH) treatment on the formation of lysinoalanine (LAL) and on in-situ and in-vivo utilisation of soya bean meal (SBM) protein were investigated. Defatted SBM was sprayed with 0 (water), 25, 50 and 100 g NaOH (kg^?1 dry matter), dried at 80°C for 2 h and then fed to four rumen cannulated goats in a 4 × 4 Latin square as a mixed diet (9: 1 w/w) of sudangrass hay and the SBM. LAL was not detected in non-alkaline SBM, but the cross-linked amino acid increased according to the level of NaOH addition. The maximum concentration of LAL was 1.26 g per 16 g nitrogen when the highest level of NaOH was applied. The NaOH treatment did not alter the digestibility or the retention of nitrogen of the mixed diet. Addition of NaOH at 25 and 50 g (kg^?1 dry matter) lowered the solubility of protein, while the highest level of treatment had little effect. Lag time and rate of degradation of protein decreased due to the increasing level in NaOH treatment. A significant correlation (r = —0.860, P < 0.01) between LAL content and rate of protein degradation suggested that the formation of cross-linked amino acid would render protein more resistant to microbial degradation in the rumen.     

Structural and physicochemical properties of soya bean protein isolate/maltodextrin mixture and glycosylation conjugates

The effect of mixture and conjugation with maltodextrin (MD) in aqueous solution on the structural and physicochemical properties of soya bean protein isolate (SPI) was investigated. Although the mixing of MD would not change the distribution of secondary structure and tertiary conformation of SPI, the protein aggregation was promoted through hydrophobic interaction, which resulted in the decrease in solubility and the improvement of gel strength and water holding capacity (WHC) of SPI/MD mixture. However, glycosylation decreased α-helix and increased β-structure. The bathochromic shift of the fluorescence emission maximum wavelength for SPI/MD conjugates was promoted, resulting in less compact tertiary conformation. These structural modifications might be the reason for the changes in the physicochemical properties of conjugates. After glycosylation, the surface hydrophobicity and solubility were increased, the average particle size was decreased, and the gelation properties were weakened including gel strength and WHC.     

蒙脱土对植物油脱色效果的综合评价北大核心CSCD

为了开发高效、环保的食用油脱色剂,以一种环保方法(半干法)生产的蒙脱土为研究对象,研究其在不同脱色条件(脱色温度、脱色时间和脱色剂添加量)下对大豆油、葵花籽油和菜籽油品质的影响。结果表明:该蒙脱土具有吸附色素和过氧化物从而降低油脂红值和过氧化值的作用,与脱色前相比,大豆油、葵花籽油和菜籽油的红值最大降幅分别为77.4%、92.3%和87.2%,过氧化值最大降幅分别为82.7%、83.2%和91.2%;蒙脱土用于3种植物油的脱色,植物油中总甾醇和总生育酚含量下降,而酸值总体上缓慢上升。进一步研究发现,在相同的脱色条件下,蒙脱土对大豆油、葵花籽油和菜籽油的酸值、总甾醇含量和吸油率的影响结果均优于活性白土,尤其是吸油率几乎是活性白土的一半。蒙脱土可替代活性白土用于对色泽要求不是很高的植物油脱色中。     

Biochemical,textural and microstructural changes in whole‐soya bean cotyledon sufu during fermentation

This study aims to investigate the nutritional value of sufu and reduce environmental problems caused by okara, which results from the traditional processing method of sufu. The feasibility of the whole‐soya bean cotyledon sufu (WSCS) processing method, which does not produce okara, was investigated. WSCS was prepared by ripening okara‐containing tofu through various hydrolytic enzymes secreted by Actinomucor elegans for 70 days. After fermentation, total nitrogen, amino nitrogen and lipid contents were found to be lower in WSCS than in traditional sufu (TS), whereas contents of reducing sugar, dietary fibre, isoflavone aglycone and soya bean polysaccharide were higher in WSCS than in TS. The hardness, springiness and adhesiveness of WSCS were 249.703 ± 0.500 g, 0.606 ± 0.008 and 8.393 ± 0.032 J, respectively. The corresponding values for TS were 264.863 ± 0.572 g, 0.615 ± 0.007 and 7.516 ± 0.031 J, respectively. In addition, microstructural changes in WSCS and TS during fermentation were observed through scanning electron microscopy. The results from this study may provide a basis for industrial production of WSCS.     

A comparative study of physico‐chemical properties and antioxidant activity of freeze‐dried mung bean (Vigna radiata) and adzuki bean (Vigna angularis) sprout hydrolysate powders

Mung bean (MB) and adzuki bean (AZB) sprouts were hydrolysed with Flavourzyme^® at four different concentrations for 6 h. Nongerminated beans subjected to each enzyme concentrations were set as the control. For both bean sprouts, the highest amounts of free amino group, total free amino acids and total phenolic content (TPC) were obtained with 7% (w/w) Flavourzyme^®. Each bean sprout hydrolysate was subjected to freeze‐drying in absence and presence of 5% maltodextrin (w/v). The addition of maltodextrin resulted in a decrease in the free amino group, TPC, surface hydrophobicity and hygroscopicity in resulting freeze‐dried powders. Gallic acid, p‐coumaric acid and vitexin were identified in all freeze‐dried powders, while catechin and rutin were detected only in freeze‐dried AZB hydrolysate powder. Freeze‐dried AZB hydrolysate powder contained higher antioxidant activities. DPPH radical scavenging activity of all samples measured using electron spin resonance spectrometry was higher than that obtained by the colorimetric method.     

废白土中油脂回收工艺与实践

以蓖麻油脱色后的废白土为原料,利用自行设计制造的专业提油设备,采用6#溶剂浸出工艺回收废白土中的油脂.工艺操作稳定,回收的油脂通过精炼可达到国际1#蓖麻油标准,脱油后的废白土残油量小于5%.介绍了专业提油设备的结构和工艺流程,讨论了生产实践中作业温度、萃取次数等因素对浸出效果的影响.     

响应面法优化山桐子油脱色工艺

对山桐子原油进行脱胶、脱酸、脱色精炼处理。考察了脱色剂种类对脱色率的影响,并以脱色率为考察指标,活性白土（优选的脱色剂）添加量、脱色温度、脱色时间为考察因素,在单因素实验的基础上结合响应面法优化山桐子油的脱色工艺。对精炼前后山桐子油的理化指标和脂肪酸组成进行了测定。结果表明：最佳脱色条件为活性白土添加量17%、脱色温度94?℃、脱色时间94 min,在此条件下山桐子油的脱色率为（91.07±0.43）%;精炼后,山桐子油的品质得到显著提升,脂肪酸组成及含量基本不变,亚油酸含量高达73.46%。     

Effects of β‐glucans on properties of soya bean protein isolate thermal gels

The effects of concentration and molecular weight of oat β‐glucans on properties of soya bean protein isolate (SPI) thermal gels prepared by heating at 90℃for 30 min were investigated. Compared with control (free of β‐glucan) formulations, the presence of β‐glucans (0.5–1.5%, w/v) largely enhanced storage modulus (G′) and texture properties of SPI (12%, w/v) thermal gels measured by dynamic oscillatory rheometry and texture profile analysis, which were developed as increasing β‐glucan concentration and molecular weight. It is possible that β‐glucans could cause the formation of protein aggregates to produce gels through hydrophobic interactions. Mixed gel systems at low ionic strength showed higher G′ resulting from the lower denaturation temperature of SPI, which was beneficial to the formation of gel structure. In addition, although adding a certain amount of β‐glucan into SPI reduced water‐holding capacity of mixed gels, high molecular weight of β‐glucan improved their water‐holding capacity compared to control formulations attributed to the improvement of the structural integrity of the mixed gel network.     

Calcium sulphate‐induced soya bean protein tofu‐type gels: influence of denaturation and particle size

Soya bean protein isolate (SPI) dispersions (7.25%, w/v) were heated at 65, 75, 85 or 90 °C for different time periods to produce SPI aggregates with diverse degrees of denaturation and particle size to investigate the effects on calcium sulphate (CaSO₄)‐induced tofu‐type gel. The results revealed that gel hardness and water‐holding capacity correlated positively with the degree of denaturation of glycinin (11S) and the particle size of the SPI aggregates. The formed gels showed more uniform and denser network structures with increasing degrees of denaturation and particle size of SPI. Hydrophobic interaction was speculated to be the crucial factor for the retention of gels prepared by SPI whose degree of denaturation by 11S was lower than 4.35%. However, disulphide bonds probably played a more important role in the retention of gels generated by SPI with the 11S denaturation degree of >84.47%. Moreover, the bulk density of the protein aggregates might determine the gel structures to a certain extent.     

Drying kinetics,physico‐chemical properties,antioxidant activity and phenolic composition of foam‐mat dried germinated rice bean (Vigna umbellata) hydrolysate

This research was aimed to study physico‐chemical properties and antioxidant activities of foam‐mat dried germinated rice bean (Vigna umbellata) hydrolysate. Germination led to an increase in released phenolic content and antioxidant activity (DPPH radical scavenging activity and FRAP) of rice bean hydrolysate. The hydrolysate obtained from germinated rice bean (GRB) and non‐germinated rice beans (NGRBs) was foam‐mat dried at 60 and 70 °C. Semi‐theoretical and empirical model could suitably describe the drying characteristic of foamed bean hydrolysate. Total phenolic content and antioxidant activities of foam‐mat dried samples decreased with increasing air‐drying temperature (P ≤ 0.05). Gallic acid, catechol and epicatechin were major phenolic compounds in foam‐mat dried samples prepared from both GRB and NGRB. The higher phenolic content and antioxidant activities were found in foam‐mat dried hydrolysate of GRB. Electron spin resonance spectrometry revealed that foam‐mat dried rice bean hydrolysate showed a strong ability to scavenge free radicals, especially carbon‐centred radicals.