稳定化处理对米糠蛋白提取效果的影响

分别利用干热、湿热、微波加热等方式对米糠进行稳定化处理,探讨了三种稳定方法对米糠蛋白质的提取及特性产生的影响。研究结果表明：三种方法均会在一定程度上影响米糠中的蛋白质提取,且干热稳定方式对米糠蛋白的提取损失程度尤为严重。稳定化处理后,所提取蛋白中的各组分含量发生了变化,且米糠蛋白的等电点由pH4附近偏移至pH6左右。     

Determination of S in extracted leaf protein.

The oxygen-combustion technique for converting organic S to sulphur oxides, absorbing these in hydrogen peroxide, and determining the sulphate formed by measuring the amount of chloranilic acid it releases from an excess of barium chloranilate, was found to give satisfactory recoveries of S from methionine and cystine. This method for determining S was then applied to extracted leaf protein concentrates, almost all of whose S is derived from methionine and cyst(e)ine.     

Effects of different enzymatic pre-press maceration treatments on the release of phenols into blackcurrant juice

The effects of different pectinolytic enzyme treatments on the release of phenolic compounds from blackcurrant berry mash into juice in experimental blackcurrant juice production were examined. The influence of enzyme dose (0–0.1% by weight), degree of berry crushing, maceration time, and temperature on the total phenol concentration, the juice yield, and on polysaccharide degradation were evaluated for four commercial, fungal enzyme preparations in statistically designed experimental templates. In optimal experimental conditions, treatments with Macer8 [FJ] and Pectinex Ultra SP-L released ~6500 and 6650 mg gallic acid equivalents/L of total phenols, respectively. These levels correspond to increases of 14–15% compared to the juice extracted without enzymes, and were significantly higher than those achieved with Rapidase BE Super and Grindamyl pectinase treatments. Increased enzyme dosage gave larger juice yields and higher phenol concentrations. There was a positive, linear correlation between degradation of the substrate polysaccharides and the amount of phenols released. The juice samples inhibited the oxidation of human low-density lipoproteins in vitro in a dose-dependent matter. The non-enzyme-treated sample exhibited higher antioxidant activity than the enzyme-treated juices at equimolar test levels of phenols, presumably because of differences in their phenolic profiles.     

Yields of extracted leaf protein from hybrid Napier grass

In connection with the production of leaf protein in quantity, the effects of fertilisers and frequency of cutting on the yields of dry matter and extractable protein were studied with hybrid Napier grass (gajraj) during 1969 to 1973 using a laboratory-scale extraction unit. The protein N extracted ranged from 21 to 38%: extractability was not affected greatly by fertiliser treatment, but there were seasonal and yearly variations. With liberal dressings of fertilisers, the crop can be expected to yield 40 metric tons of dry matter, 6000 kg of crude protein and about 2000 kg of extractable protein from a hectare per year in India. The fibrous residue, even after two extractions, contains 6 to 12% of crude protein and could still be used as cattle feed.     

红外烘烤对水代法制取芝麻香油品质的影响

以白芝麻为原料,研究红外烘烤条件对水代芝麻香油品质的影响。结果表明:随着红外烘烤温度的升高及烘烤时间的延长,芝麻香油的色泽加深、诱导时间延长、过氧化值增大,而对酸价的影响不显著。      

不同热处理对藜麦蛋白质营养品质的影响

本研究分别采用微波、蒸制、煮制和烘焙对藜麦分离蛋白（QPI）进行热处理,并评价处理前后QPI氨基酸组成、体外消化特性和生理活性变化。结果表明：蒸制、煮制和烘焙处理分别使QPI中必需氨基酸总量降低了2.93%、8.68%和1.91%（p<0.05）,同时改变了QPI中氨基酸的组成及评分;微波和煮制处理后QPI最终消化率分别提高至77.10%和82.86%（p<0.05）;在测定浓度范围内,各组QPI消化产物均展现出体外抗氧化活性,其中微波处理组样品DPPH自由基清除能力（42.71%）及氧自由基吸收能力最强（34.90%）; QPI消化产物能够促进3T3-L1脂肪细胞胰岛素抵抗模型对葡萄糖的摄取,蒸制、煮制和烘焙能够进一步提高该效果（p<0.05）。该研究为藜麦蛋白质的加工和功能性应用提供理论指导,旨在促进藜麦产业的进一步发展。     

冷藏处理方式对南美白对虾品质的影响

研究致死方式和贮藏温度对南美白对虾感官和质构品质的影响,对感官和硬度、弹性、内聚性等参数的变化进行品评和测定。结果表明:南美白对虾在冰水中5min内即可致死,经48h贮藏后的感官分值为20.3,符合食用标准,而自然死亡的虾在24h时就已不能食用,故冰水致死法能有效保持原料的新鲜品质;冰猝致死的虾-21℃贮藏30d时的硬度、弹力和内聚性分别是-7℃贮藏的1.24、1.5和1.15倍,而-7℃下贮藏虾的感官分值为17,已不可食用,故较低贮藏温度更有利于保持南美白对虾的新鲜度和产品品质。     

不同加工方法对速冻水饺皮品质的影响

采用水煮、微波熟化、微波复热三种加工方法,通过物性仪测定不同熟化方式对速冻水饺皮品质的影响。结果显示:和水煮速冻水饺皮的物性指标相比,微波复热导致水饺皮的煮后强韧性降低,硬度增大,回复性降低;微波熟化水饺皮的煮后强韧性和弹性没有明显的变化,但能提高水饺皮的咀嚼度68%,回复性24%;因此微波熟化是一种可以代替水煮加工的方法。      

Protein extraction from pasture: Effect of crop species and of a reducing agent on the quality of extracted protein

Leaf protein concentrations (LPC) were prepared from herbage harvested from pure stands of ryegrass (Lolium perenne), white clover (Trifolium repeens), lucerne (Medicago sativa cv. Wairau) and from a stand of ryegrass/white clover dominant pasture: each crop was processed with and without the addition of sodium metabisulphite just prior to pulping. Protein quality was measured by rat growth and in-vivo rat true digestibility. Juice protein composition was measured and was related to chemically available lysine and protein true digestibility. Protein in ryegrass LPC had a lower digestibility (72%) than that from white clover (81%) or lucerne (78%), due to a higher proportion of the juice true protein being from the chloroplastic fraction for ryegrass (73%) compared with the two legumes (49–56%). The chloroplastic fraction is of inherently lower digestibility than the cytoplasmic fraction. Metabisulphite treatment at pulping caused a small but consistent increase of chemically available lysine in the LPC, and also improved chemically available methionine and protein utilisation for growth. Effects on protein true digestibility were inconsistent. When LPC was fed with a methionine supplement, the efficiency of utilisation of protein for growth did not differ amongst the four crops. This occurred despite the true digestibility of protein on LPC being higher for the legumes than for ryegrass and ryegrass/white clover.     

Protein extraction from pasture: Effect of crop species,regrowth age and season on the quality of the extracted protein

Leaf protein concentrates (LPC) were prepared from ryegrass (Lolium perenne), white clover (Trifolium repens), lucerne (Medicago sativa cv. Wairau), and from ryegrass/white clover dominant pasture, harvested after a range of regrowth intervals in spring, summer and autumn seasons. Protein quality was measured by rat growth (to give Relative Nutritive Value, RNV) and in-vivo rat true digestibility. RNV for LPC prepared from all crops was about 50% of that for lactalbumin. Results were highest for lucerne and lowest for ryegrass and ryegrass/white clover. When LPC was supplemented with methionine, RNV improved to 80–90% of that for lactalbumin. Quality was highest and similar for white clover and lucerne and lowest and similar for ryegrass and ryegrass/white clover. The true digestibility of protein was highest for lucerne (82%) and lowest for ryegrass and ryegrass/white clover (70%). These variations may be related to the proportions of cytoplasmic and chloroplastic protein in the juice. There was no effect of season (autumn vs spring) or age of herbage at harvest (4, 6, or 8 weeks regrowth) on the quality of protein. Despite standardised procedures for harvesting, processing, and drying the LPC and for assessing protein quality, undefined factors caused variation in methionine-supplemented protein quality.     

何首乌叶对小曲质量的影响研究

探讨了不同的何首乌叶添加量对小曲中的微生物种类和数量、糖化力、液化力及发酵力的影响.结果表明当何首乌叶的添加量为6%时,霉菌数为7.72×104个/g干曲,酵母数为4.28×103个/g干曲,细菌数为1.27×103个/g干曲;小曲的糖化力、液化力、发酵力分别为472mg/(g·h)、7.96g/(g·h)、68.3%.此时小曲外观为淡黄色,无黑心,具有特殊的浓酒香.     

银杏叶添加量对啤酒品质的影响

通过对啤酒生产中麦汁和发酵液的检测,研究了银杏叶的不同添加量对于麦芽汁和发酵液品质的影响,并确定了银杏叶最适添加量范围,在此范围内发酵液中黄酮含量为33.6～59.6mg/L,银杏酸含量＜10mg/L,符合国家药典标准.     

Functional properties of sonicated and non-sonicated extracted leaf protein concentrate from Diplazium esculentum

Leaf protein concentrate of edible fern Diplazium esculentum was extracted using sonication and non-sonication methods and its functional properties were evaluated. The leaf protein concentrate contained 34.28 and 9.89% protein for sonicated and non-sonicated extractions, respectively. Sonication yielded (36.36%) better emulsion activity over non-sonication (31.10%). Foaming capacity was also found better in sonication (7.27%) over non-sonication (6.99%), and oil absorption capacity also improved in sonication (7.55 g of oil/g) over its counterpart (7.41 g of oil/g). Contact angle experiments with the leaf protein concentrate evidenced the enhancement of more hydrophilicity of the sonicated sample. Thermal properties of the leaf protein concentrate with sonication evidenced more stability (55.58 and 95.95°C) over the non-sonicated (46.75 and 75.60°C). Fourier transform infrared spectral analysis with the leaf protein concentrate of Diplazium esculentum was used to assess the secondary structural data such as α-helix and β-sheets. The various percentages of secondary structures of protein in sonicated and non-sonicated samples were 49.06 and 69.16% for α-helix, 33.59% and 17.02% for β-sheet and 42.02 and 35.68% for turn, respectively. The results of the present investigation showed credible evidence to support that sonication method of extraction of leaf protein concentrate was better in terms of protein yield and functional properties as compared to the non-sonication. The sonicated extracted leaf protein concentrate has the potential for developing value added products.     

The yields of extracted leaf protein from lucerne (Medicago sativa L.)

The effects of fertilisers, frequency of cutting, row spacing and simazine on the yields of dry matter and extractable protein from lucerne (Medicago sativa L.) were studied using the laboratory-scale pulper and press. Between 40 and 65% protein nitrogen was extractable; extractability was not affected by the various treatments but altered with season. Lucerne responded with increased yields of dry matter and extractable protein to fertilisers, simazine (35 g/ha) and rows spaced at 30.5 cm. Six or 8 harvests were found to give greater yields than 5 harvests in 180 days. The annual yields of extractable protein reached 3100 kg/ha and it is felt that better control of pests could lead to even greater yields.     

不同方式处理的绿豆对面包品质的影响

本文研究了煮制、微波和超高压三种方式处理的绿豆对绿豆面包品质的影响。试验结果表明,粒径为80目和100目的绿豆制备的绿豆面包在主观可接受性和客观质构特性方面均明显优于60目绿豆面包,并且80目和100目绿豆面包的品质之间差异不显著。不同方式处理的绿豆部分替代小麦粉制备的绿豆面包在品质上存在较大差异,其中超高压处理的绿豆显著改善了绿豆面包的品质。与对照组相比,绿豆经超高压处理后,绿豆面包的感官品质显著提高,并且面包的比容、弹性、内聚性和回复性等质构指标均增大,而硬度、胶着性和咀嚼性有明显减小。经煮制和微波处理的绿豆制备的绿豆面包在总体的可接受性上均有提高,而在硬度、胶着性和咀嚼性等质构特性指标上,微波处理绿豆制备的绿豆面包品质有更明显的改善。因此,相比于煮制处理,微波法处理绿豆对绿豆面包品质的改善效果更佳。试验结果表明,绿豆经超高压处理后过80目筛可以有效改善面包因添加绿豆而产生的感官和质构方面的问题,提高绿豆面包的品质。     

中低温蒸汽处理对鲜切胡萝卜片减菌效果及其品质的影响

以鲜切胡萝卜片为研究对象,采用中低温蒸汽(50～100℃)进行减菌处理,分析了蒸汽处理过程中鲜切胡萝卜片品质指标的变化。结果表明,鲜切胡萝卜片的菌落总数、水分、类胡萝卜素、硬度、色泽等指标均随处理温度及时间的增加而显著减少(P<0.05)。采用低温蒸汽(50～70℃)处理600s,对胡萝卜片的减菌效果明显,且失水率小于5%,类胡萝卜素保留高于85%,对蔬菜的硬度和色泽影响较小。而经中温蒸汽(80～100℃)及传统的沸水热烫处理后的胡萝卜片,其品质质地明显降低。因此,低温蒸汽减菌处理能有效降低胡萝卜片中的菌落总数,并可最大程度保护其品质质地。     

桑叶对小曲质量的影响研究

研究了不同添加量的桑叶对小曲的微生物种类和数量、糖化力、液化力及发酵力的影响。结果表明,在一定范围内添加桑叶对小曲质量具有良好的促进作用,其合理添加量为9％,制成的小曲霉菌数达4．58×10^4个／g干曲,酵母数达4．77×10^3个／g干曲,细菌数达2．05×10^3个／g干曲。糖化力、液化力及发酵力分别达到498．2mg／g·h、0．82g／g·h、65．1％。