ENZYMATIC HYDROLYSIS PRETREATMENT TO SOLVENT EXTRACTION OF SOYBROKENS FOR ENHANCED OIL AVAILABILITY AND EXTRACTABILITY

Response surface analysis of enzymatic hydrolysis of soybrokens was conducted and the parameters were optimized to enhance both the oil availability and the oil extractability. The parameters, with their levels investigated, were: moisture content during hydrolysis (18.1–27.9% wet mass basis), enzyme concentration (7.1–16.9% volume/weight of sample) and hydrolysis period (2.1–21.9 h). For soybrokens, the enzymatic hydrolysis pretreatment increased both the oil availability by 1–2 percentage points and the oil extractability by 1.3–4 percentage points. The effect of enzymatic concentration was insignificant. The recommended parameter values are: 24–25% w.b. moisture during hydrolysis, 7.1% v/w enzyme concentration and 13.5–14.5 h hydrolysis period.     

大豆分离蛋白的提取及其改性方法

概述了大豆分离蛋白的传统提取法、膜分离法、泡沫分离法、双极膜法及其通常所用的改性方法 ：热处理法，酸处理和酶处理法。     

CHANGES IN TENDERNESS OF BEEF LONGISSIMUS DORSI AS RELATED TO MUSCLE COLOR AND pH

Longissimus dorsi shear values for carcasses of 168 steers, 147 heifers and 259 bulls, all slaughtered in the age range of 12–16 months, were correlated with postmortem pH values and postmortem change in pH. Neither the individual pH values nor degree of postmortem pH change were useful predictors of shear value for steer and heifer carcass (r² values less than 0.07). For bull carcasses, pH of the longissimus dorsi taken 24 hr postmortem was significantly correlated with shear value, (r =−0.7) and with meat color (r =+0.7). Sexes differed markedly in the range of 24 hr pH of the longissimus dorsi with none of the steers, 8% of the heifers and 49% of the bulls having values greater than 6.0.     

大豆胚芽中异黄酮和皂甙同步提取工艺的研究

大豆异黄酮和大豆皂甙是大豆中的活性成分。本文主要研究了同时从大豆中提取这两种物质的工艺条件，通过溶剂对比实验、单因素实验确定了从大豆粕中提取大豆异黄酮和大豆皂甙的最佳工艺，并通过正交实验优化最佳生产工艺条件：温度55℃、固液比1：18、80％的乙醇溶液、提取时间2h、提取两次，异黄酮和皂甙得率分别为1．53％和4．07％。     

ENZYMATIC HYDROLYSIS OF SOYBEAN FOR SOLVENT AND MECHANICAL OIL EXTRACTION

Due to inefficient extractability of its low oil content, soybeans are often bypassed in village‐scale processing. Soygrits, flakes, and expanded collets were hydrolyzed by proteases, cellulases, and pectinases before oil extraction by solvent and static mechanical pressure. Driselase with multi‐enzyme activity and two proteases improved solvent extraction rates but only Driselase enhanced mechanical pressing. Up to 58% of seed oil was pressed from enzyme‐hydrolyzed flakes but 88% was pressed from Driselase‐treated collets. Either pretreatment is a feasible adjunct to mechanical pressing in small batch operations.     

黑豆多糖的提取工艺及稳定性研究

采用热水提取法来获得黑豆多糖,对其提取工艺进行优化研究,并探讨黑豆多糖的稳定性.结果表明提取的最佳条件为:料液比为1:20,提取温度为90℃.提取时间为4h.此条件下黑豆多糖的提取率为0.396%.黑豆多糖耐热性较差,稳定性受光照影响较小,耐氧化性较好,且不易被还原.pn值在5.0-7.0范围内,黑豆多糖有良好的稳定性.     

大豆胚轴中异黄酮的提取及其抗血小板聚集作用的研究

从大豆胚轴提取总糖苷后，采用C18反相柱层析法分离大豆异黄酮糖苷，再将其水解制备成异黄酮苷元，并研究大豆异黄酮对人血小板聚集性的影响。结果：在体外人血小板聚集实验中，大豆异黄酮苷元均抑制ADP、胶原蛋白和肾上腺素诱导的血小板聚集。提示：大豆异黄酮可能有助于防止血栓形成。     

AQUEOUS ETHANOL EXTRACTION OF SOYBEAN TRYPSIN INHIBITORS AND CHARACTERIZATION OF A CALCIUM-SENSITIVE FRACTION

The trypsin inhibition by an 85% aqueous ethanol extract of soybeans was shown to have many similarities to that exhibited by long chain fatty acids and their acyl CoA esters, in terms of concentration dependence, time dependence and susceptibility to Ca⁺⁺ suppression. The heat-stable and hexane-extractable inhibitor in the extract was thus referred to as the Ca⁺⁺ -sensitive fraction, in contrast to classic proteinaceous inhibitors. Tempeh fermentation increased the antitryptic activity of the 85% ethanol extract. Extraction of both classic and Ca⁺⁺ -sensitive inhibitors from soybeans by aqueous ethanol was found to be concentration dependent. Aqueous solvents with less than 20% ethanol removed classic inhibitors as effectively as water, but extracted no Ca⁺⁺ -sensitive one. Above 20% ethanol in the solvent, the classic inhibitors in the extract decreased until reaching a zero value at 70% ethanol concentration, while the Ca⁺⁺-sensitive fraction increased to a maximum at 85%.     

大豆异黄酮的热水提取及其纯化工艺的优化

研究了热水从大豆胚芽中提取异黄酮的工艺，方法简便、可行且提取率、纯度满足实验要求；并采用HPLC法对提取液中异黄酮组分进行鉴定。经大孔树脂纯化、乙酸乙酯萃取三次后，异黄酮纯度超过60％。     

EXTRACTION YIELD OF SOLUBLE PROTEIN AND MICROSTRUCTURE OF SOYBEAN AFFECTED BY MICROWAVE HEATING

A laboratory‐scale microwave (MW)‐assisted extraction system was constructed and compared with a conventional shaking water bath regarding the extraction of soluble proteins in soybeans. Dynamic reaction was monitored by response surface methodology in the MW‐assisted extraction system. The yield of soluble protein increased until either temperature (T) or water/solid (W/S) ratio reached an optimum point (60.1C, 12.6 mL/g), and then decreased with further increase of T or W/S ratio. In addition, the yield of soluble protein increased with time within a range of 30 min, and no critical point was observed. The molecular mass of soluble protein was distributed from 19.3 to 81.3 kDa estimated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Scanning electron microscopy showed the destruction of the microstructure of soybean cells, which increased the extraction of soluble soy protein.     

双相溶剂萃取技术提取酱油渣中油脂和大豆异黄酮的研究

利用正己烷-乙醇-水构成的双相溶剂萃取技术同时从酱油渣中提取油脂和大豆异黄酮,采用正交设计方法,考察温度、时间、乙醇浓度、乙醇用量、正己烷用量对油脂和大豆异黄酮提取率的影响,并用极差分析方法对正交试验结果进行分析。确定最优的提取条件：温度60℃、乙醇浓度80％、乙醇用量0．071g／mL、正己烷用量0．1g／mL、时间2h,在此条件下,油脂提取效率为99．2％,大豆异黄酮提取效率为94．5％。     

微波提取水溶性大豆多糖工艺研究

采用正交实验法对微波提取豆渣中水溶性大豆多糖进行研究,试验的优化工艺条件为:微波功率为700 W,微波时间为120 s,固液比为1:2,在此条件下的大豆多糖提取率为1.806 4%.实验证明,加热4次、过滤4次、合并滤液的微波提取方法,可以达到理想的水溶性大豆多糖的提取效果(提取率10.5447%).     

AQUEOUS EXTRACTION OF OIL AND PROTEIN FROM SOYBEAN AND LUPIN: A COMPARATIVE STUDY

This study compares the effects of extrusion pretreatment and protease addition during aqueous extraction processing (AEP) of soybean and lupin flakes. AEP of flakes resulted in the lowest yields of oil (56%), protein (71%) and [cream  +  free oil] (8%) for soybean, while for lupin, yields were 48, 69 and 2%, respectively. AEP protein extraction yields were decreased by extrusion pretreatment, but this pretreatment improved enzymatic action, increasing protein extractability from soybean and lupin by 47 and 26%, respectively. For both protein crops, enzyme-assisted AEP (EAEP) of extruded flakes yielded the highest oil, protein and [cream  +  free oil] yields, which were 96, 85 21%, respectively, for soybean. Yields for lupin were 81, 77 and 10%, respectively. Extrusion followed by enzyme addition positively impacted demulsification yield, the creams from EAEP of soybean and lupin extruded flakes being the less stable toward enzymatic demulsification .

PRACTICAL APPLICATIONS

The vegetable oil industry is looking for alternatives to the traditional solvent extraction of oil-bearing seeds, and there is a need to increase the inefficient conventional aqueous extraction of protein from residual defatted meal, a by-product of the oil extraction process. The concept of enzyme-assisted aqueous extraction processing (EAEP) has been successfully developed for extruded soybean material, but its efficiency on other oil-bearing seeds still needs to be demonstrated. By determining the oil and protein extraction yields recovered during EAEP of extruded lupin flakes, the feasibility of transferring this process from soybean to other oilseeds will be established.     

CHEMICAL AND PHYSICAL ATTRIBUTES OF MUSKMELON RELATED TO TEXTURE

Effects were investigated of certain physical and chemical characteristics on muskmelon texture as described by sensory evaluation. Turgor pressure, moisture content and concentrations of total sugars, alcohol insoluble solids, three pectin fractions, starch and cellulose were determined in 50 melons purchased randomly from a retail market. Sensory assessments included crispness, fibrous-ness, and resistance to cutting, biting and crushing. Results indicated that the texture of muskmelon is determined largely by the type and amount of cell wall constituents. Maturity, inferred from starch and protopectin content, also affected sensory panel scores. Moisture, alcohol insoluble solids, total sugars and pectic substances, except protopectin, were not reliable texture indicators. Although turgor pressure was not related significantly to any textural characteristics, a trend was observed suggesting that this variable warrants further investigations.     

ELECTROPHORETIC STUDY OF SUBSTRATE AND pH DEPENDENCE OF ENDOPROTEOLYTIC ENZYMES IN GREEN MALT*

The endoproteolytic enzymes of malt influence several different aspects of malt and beer quality. For this reason, we are extracting and characterizing these enzymes from green malt. The proteolytic activity of a Morex green malt extract was highest at pH 3.8 with haemoglobin substrate but gelatin hydrolysis was maximal from pH 4.7 to 6.0. Endoproteolytic hydrolysis of a 55% isopropanol-soluble reduced hordein fraction was about three times slower than gelatin hydrolysis but was relatively constant over the pH range from 3.8 to 6.5, although the activity did decrease at more acidic (3.0) or basic (7.0) pH values. To study the green malt proteinases in detail, a non-denaturing electrophoretic system was developed in which substrate proteins—either gelatin, edestin or hordein—were incorporated into an electrophoretic gel. After electrophoresis and incubation of the gels at pH 3.8, 4.7, 5.5, or 6.5 to allow enzymatic hydrolysis, the separated activities were determined by using protein staining to determine where the incorporated substrate had been hydrolysed. Using this system, seven proteolytic activity bands were detected. Five of the bands were maximally active at pH 3.8 and their activities dropped quickly as the pH increased. The other two bands, which migrated more slowly, hydrolysed gelatin more rapidly than they did the other substrates tested. Their gelatinolytic activities increased as the pH was raised (by 3- to 6-fold in the pH range tested). The electrophoretic system described has proven very useful for studying the proteinases of germinating barley seeds. The results indicate that much past research on malt proteinases may not be particularly relevant to the malting and brewing industries because it was conducted under pH conditions and with substrates that are likely quite different from those in the seed during the barley germination process. By using electrophoresis to separate proteinases before analysis, we can now study their individual characteristics and thus can conduct studies more relevant to malting and brewing.     

THE METABOLISM OF PUTRESCINE,SPERMIDINE AND SPERMINE BY YEAST IN RELATION TO THE AVAILABILITY OF MAGNESIUM

During the lag period immediately after inoculation of yeast into a defined salts medium rapid changes in the internal concentrations of the oligoamines occurred when the medium was deficient in magnesium or high in calcium. Pronunced changes in the oligoamine content of yeast also occurred after inoculation into a range of worts and the extent of the effect appeared to depend on the magnesium content of the wort. The amount of magnesium in all the worts was much higher than was found to be saturating in a minimal medium and it therefore seems that the magnesium in worts is not freely available to the yeast cells. Putrescine was the only oligoamine found in wort and was present at about 1 mg/litre. The putrescine concentration in the wort always increased during fermentation and the period of most rapid increase corresponded to the period of decline in the internal oligoamine pools.     

大豆胚芽油提取工艺的研究

以大豆胚芽出油率为指标，石油醚为脱脂溶剂，通过单因素和正交试验对大豆胚芽索氏提取工艺进行了研究。结果表明：大豆胚芽制油的最佳提取工艺为：粒度30目，料液比1：13，回流时间5h。在此条件下，大豆胚芽出油率为10．50％。