永春芦柑果皮提取物抗氧化性能的研究

分别用乙醇、乙醚、乙酸乙酯三种不同的有机溶剂对永春芦柑的果皮进行提取。提取物分别添加到猪油、花生油中，并测定不同条件下的过氧化值（POV）。结果显示：不同溶剂的永春芦柑果皮提取物都具有一定的抗氧化活性。在猪油当中，乙酸乙酯提取物的抗氧化能力优于其它溶剂的提取物；而对花生油则是乙醇提取物的抗氧化能力较高。把三种溶剂的提取物经过高温处理后，发现乙酸乙酯提取物的耐热性较好。     

Substrate and parasubstrate regulation of physiological processes at various levels of the organization of living systems as illustrated by examples of the regulation of appetite, of the specific dynamic action of food and of the inhibition of processes of absorption]

It was demonstrated that in the organism of higher animals the adaptation regulation of food uptake and nutrient absorption and transport comprises, in addition to the classic mechanisms of substrate regulation, specialized non-substrate and parasubstrate mechanisms which control the uptake of food and other substrates at all three levels (organosystemic, organic and cellular). As to the organosystemic level, it was observed in duodenectomized rats that appetite inhibition is produced not only by a stimulation of the receptors and by an increase in the concentration of the food substrates and of the metabolites in the blood, but also by one of the intestinal appetite-inhibiting hormones, arenterin. As to the organic level, it was evidenced that the enzymatic and transport functions of the small intestine and the numerical composition of the enterocyte population in the different segments are determined by the substrate load on the respective areas of the small intestine as well as by the blood and chyme-mediated intersegmental reactions in the small intestine. As to the tissular and cellular levels, the possibility of a regulation of the enzymatic and transport systems of the microvilli by means of substrates contained in the mucous membrane of the small intestine and endogenous substances (permein and antipermein) was evinced.     

The effects of environmental conditions on the lipolytic activity of strains of Penicillium roqueforti

The lipolytic activity of 30 strains of Penicillium roqueforti was investigated by agar diffusion tests on tributyrin (esterase activity) and olive oil agar (lipase activity), by titration of the free fatty acids (FFA) produced and by gas chromatographic analysis of the individual FFA released after growth at 25 or 10 degrees C in butterfat emulsions containing 0, 2 or 7% NaCl. All strains investigated by the agar diffusion tests possessed esterase activity and 23 strains were also able to hydrolyse olive oil, but differences in esterase activity were seen. The agar diffusion tests and the titration of FFA showed that the amount of FFA released by a strain of P. roqueforti is determined by both esterase and lipase activity. A large release of FFA was only seen for strains with the ability to hydrolyse both short- and long-chained fatty acids, while strains with esterase activity produced smaller amounts of FFA. Between 7 and 14 days of incubation a steep increase in the release of FFA was observed both by the titration and by GC analysis, and then a decline from 14 to 21 days, probably caused by conversion of FFA to methyl ketones. Identical FFA profiles were found for two strains with different lipolytic activity. Long-chained fatty acids dominated the profile, while the short-chained fatty acids only were detected in small amounts and mainly in the end of incubation. Both strains were stimulated by NaCl in the emulsions.     

两种酒曲制备米酒品质对比研究

该研究用两种不同的酒曲制作米酒,并对两种酒曲的糖化液化、能力及其发酵米酒的pH、总糖、酒精度、氨基酸态氮、总酸和 可溶性固形物含量的变化情况进行测定,且采用气相色谱-质谱联用技术（GC-MS）分析不同酒曲发酵米酒中挥发性风味物质的成分 差异。 结果表明：酒曲2发酵米酒的总糖、酒精度、氨基酸态氮和可溶性固形物都明显优于酒曲1。 酒曲1发酵米酒中检测出24种物质。 酒曲2发酵酒中共检测出23种成分。主要为醇类、酯类、酸类和醛类物质,两种酒曲发酵米酒主要风味成分组成种类基本相同,差异主 要表现在成分相对含量上。 酒曲1发酵米酒主要挥发性物质有丙酸（41.85%）、乙酸（31.48%）、糠醛（9.99%）、乙醛（6.90%）,酒曲2发酵 米酒主要挥发性物质有丙酸（65.86%）、乙酸（17.68%）、戊酸乙酯（4.06%）、乙醛（3.46%）。     

Complex experimental assessment of potential allergenicity of various isolates of soy proteins

The complex evaluation was carried out of potential allergenicity of three soya protein specimens - IPS, IPS-1 and IPS-2 manufactured by Ardex R, USA, which were attended for employment as protein component of specialized infant formulae. The content of total protein, amino-nitrogen, peptide fractions of molecular weight below 9000 D, precipitating protein antigens, trypsin inhibitor, was studied in the specimens. The apparent digestibility was measured by a multienzymatic system in vitro. The allergenicity of isolates was compared by means of histamine LD50 resistance test in guinea pigs and also by the reaction of active anaphylactic shock (AAS). The evidences have been obtained that IPS specimen containing the lowest levels of trypsin inhibitor and small peptide levels is characterized by the lowest sensitizing activity in AAS and simultaneously decreases the animals' resistance to histamine in the highest degree. Apparent digestibility of all the three specimens did not differ significantly. A conclusion has been made that the evaluation is necessary of infant hypoallergenic formulae components by a complex of independent experimental data.     

Effects of timing of palmitic acid supplementation on production responses of early-lactation dairy cows

The objective of our study was to evaluate the effects of timing of palmitic acid (C16:0) supplementation on production responses of early-lactation dairy cows. Fifty-two multiparous cows were used in a randomized complete block design experiment. During the fresh period (FR; 1–24 d in milk) cows were assigned to either a control diet containing no supplemental fat (CON) or a diet supplemented with C16:0 (palmitic acid, PA; 1.5% of diet dry matter). During the peak (PK) period (25–67 d in milk) cows were assigned to either a CON diet or a PA (1.5% of diet dry matter) diet in a 2 × 2 factorial arrangement of treatments considering the diet that they received during the FR period. During the FR period, we did not observe treatment differences for dry matter intake or milk yield. Compared with CON, PA increased the yield of 3.5% fat-corrected milk by 5.30 kg/d, yield of energy-corrected milk (ECM) by 4.70 kg/d, milk fat content by 0.41% units, milk fat yield by 280 g/d, and protein yield by 100 g/d. The increase in milk fat associated with the PA treatment during the FR period occurred due to an increase in yield of 16-carbon milk fatty acids (FA) by 147 g/d (derived from both de novo synthesis and extraction from plasma) and preformed milk FA by 96 g/d. Compared with CON, PA decreased body weight (BW) by 21 kg and body condition score (BCS) by 0.09 units and tended to increase BW loss by 0.76 kg/d. Although PA consistently increased milk fat yield and ECM over time, a treatment × time interaction was observed for BW and BCS due to PA inducing a greater decrease in BW and BCS after the second week of treatments. Feeding PA during the PK period increased milk yield by 3.45 kg/d, yield of 3.5% fat-corrected milk by 4.50 kg/d, yield of ECM by 4.60 kg/d, milk fat content by 0.22% units, milk fat yield by 210 g/d, protein yield by 140 g/d, and lactose yield by 100 g/d but tended to reduce BW by 10 kg compared with CON. Also, during the PK period we observed an interaction between diet fed in the FR and PK periods for milk fat yield due to feeding PA during the PK period increasing milk fat yield to a greater extent in cows that received the CON diet (+240 g/d) rather than the PA diet (+180 g/d) during the FR period. This difference was associated with the yield of preformed FA because feeding PA during the PK period increased the yield of preformed milk FA only in cows that received the CON diet during the FR period. In conclusion, feeding a C16:0 supplement to early-lactation cows consistently increased the yield of ECM in both the FR and PK periods compared with a control diet. For some variables, the effect of feeding C16:0 was affected by timing of supplementation because milk yield increased only during the PK period and BW decreased to a greater extent in the FR period. Regardless of diet fed in the FR period, feeding a C16:0 supplement during the PK period increased yields of milk and milk components.     

多粮浓酱兼香型白酒酿造过程中窖内糟醅温度变化

比较分析了多粮浓酱兼香型白酒新工艺和传统多粮浓香型白酒工艺窖内发酵糟醅温度的时空变化情况。结果表明。2种工艺条件下窖内糟醅温度变化趋势均呈现主升温期缓慢、顸温维持期较长、温度回落期缓慢;贴近窖壁糟醅温度最低,中心糟醅温度最高,但是2种糟醅的具体出窖温度、平均温度、顶温,以及主升温时间、温度维持时间、温度回落时间却呈现出明显的差异性。     

Estimation of Amylose Content of Starches after Precipitation of Amylopectin by Concanavalin-A

The estimation of the amylose content of starches has been studied by precipitating the amylopectin with concanavalin-A and then, after denaturing the remaining concanvalin-A by heat, determining the unprecipitated glucan in the supernatant by (a) hydrolysis with amyloglucosidase: α-amylase followed by glucose oxidase-peroxidase reagent, (b) colorimetrically with phenol-sulphuric acid or (c) by colour with iodine.     

Binding of Taurocholate by Pectin in the Presence of Calcium Ions

Binding of taurocholate by pectin was examined in vitro, using low-methoxyl pectin and calcium lactate. Water in calcium pectate gel was partially separated from the gel by filtration through a glass-filter. Taurocholate bound by pectin was calculated after measurement of taurocholate in the filtrate by the UV absorption method. The amount of taurocholate bound by pectin increased linearly with increase in pectin concentration but independent of time. One gram pectin bound a maximum of 6.0 μmole of taurocholate.     

Improvement of functional properties of bovine serum albumin through phosphorylation by dry-heating in the presence of pyrophosphate

ABSTRACT:  Bovine serum albumin (BSA) was phosphorylated by 2 methods. One is dry-heating in the presence of pyrophosphate, and the other is conjugation with maltopentaose through the Maillard reaction and subsequent dry-heating in the presence of pyrophosphate. The phosphorus content of BSA was increased to approximately 0.45% by dry-heating at pH 4.0 and 85 °C for 5 d in the presence of pyrophosphate, and approximately 0.91% by glycation and subsequent phosphorylation. The circular dichroism spectra showed that the change of secondary structure in the BSA molecule by phosphorylation was mild. However, tryptophan fluorescence intensity of BSA decreased by phosphorylation. The differential scanning calorimetry thermograms of BSA showed a disappearing of the 1st peak and a lowering of the 2nd peak denaturation temperature by phosphorylation. These results indicated molten (partially unfolded) conformations of BSA formed by both phosphorylation methods. The functional properties of BSA such as heat stability and calcium phosphate solubilizing ability were improved by phosphorylation alone and further by phosphorylation after glycation. Transparent gels of BSA with relatively high water-holding capacity were obtained by phosphorylation alone, and the immunogenicity of BSA was reduced significantly by glycation and phosphorylation, respectively.     

鼠李糖乳酸杆菌对河豚肝脏中河豚毒素毒性的影响

以野生河豚肝脏中的河豚毒素（tetrodotoxin,TTX）为研究对象,研究活化与热灭活处理的鼠李糖乳杆菌对其毒性的消减作用。将活化的与热灭活处理的鼠李糖乳杆菌作为材料对TTX进行脱除,采用酶联免疫吸附剂测定（enzyme-linked immunosorbnent assay,ELISA）、层析试纸检测和小鼠生物法分析TTX消减率的变化,采用气相色谱-质谱分析发酵处理后的肝脏二十碳五烯酸（eicosapentaenoic acid,EPA）与二十二碳六烯酸（docosahexaenoic acid,DHA）含量变化。竞争性ELISA结果显示加热灭活后的鼠李糖乳杆菌对TTX的消减率高达82.16%;而未经灭活处理的鼠李糖乳杆菌对TTX的消减率为70.05%,表明热灭活处理的鼠李糖乳杆菌消减效果更佳。此外,经鼠李糖乳杆菌发酵7 d后野生河豚肝脏的TTX消减率为93.27%,气相色谱-质谱检测结果显示发酵后肝脏内的EPA与DHA含量分别减少了11.93%、22.50%。综上所述,鼠李糖乳杆菌能消减河豚肝脏中的TTX,经鼠李糖乳杆菌发酵处理后消减效果更佳,本研究结果可为河豚内脏组织的毒性消减提供参考。     

Theory of Heterosis

The theory of heterosis is expressed by simple genetic models. Relevant population means are deduced for differences in gene frequencies among populations. Heterosis for the one-locus, two-allele model is a function of the square of the difference in gene frequency multiplied by the dominance deviation. Heterosis, for a model with two loci and two alleles at each, contains an additive by additive epistatic term as well. Recombination loss in the F₂ or the mating of similar crosses interse is a function of the recombination fraction between loci, differences in gene frequencies, and additive by additive and dominance by dominance epistatic effects.     

马肉中脂肪酸组成及含量的气相色谱-质谱法分析

采用气相色谱-质谱法分析了马肉中脂肪酸的化学组成及各成分的含量。马肉中的脂肪经正己烷提取、硫酸-甲醇酯化法甲酯化、GC-MS测定、总离子流图峰面积归一化法测定各组分相对含量。马肉中饱和脂肪酸含量为38.4%,不饱和脂肪酸为61.6%,其中单不饱和脂肪酸为44.8%;马肉脂肪酸中油酸含量最高,其它由高到低依次为棕榈酸、亚麻酸、棕榈油酸、亚油酸、硬脂酸、肉豆蔻酸、花生四烯酸。结果表明,马肉中脂肪酸能较好地满足人体的营养需求。     

豌豆分离蛋白对小麦粉面团特性及挂面品质的影响

研究豌豆分离蛋白(PPI)添加量对小麦粉面团蛋白质组成、粉质特性、拉伸特性和对挂面断裂强度、烹煮特性及感官品质的影响。结果表明:添加PPI后面团中23.8~100.1 ku的蛋白条带明显加深;当添加量为9.0%时,面团吸水率提高8.0%,稳定时间延长36.6%,拉伸阻力提高83.2%,拉伸比增大176.2%,说明PPI的添加能够提高面团的筋力;PPI添加量达到7.0%时,挂面最佳烹煮时间降低11.8%,生挂面断裂强度提高34.0%,同时熟挂面的硬度、胶着性和咀嚼度有不同程度的提高。感官品评表明,添加3.0%~7.0%PPI制备的挂面与普通挂面无显著差异。     

低温等离子体降解呕吐毒素效果评价及降解规律解析

小麦赤霉病导致的真菌毒素污染是影响小麦质量安全的关键因素,如何削减呕吐毒素(DON)污染是当前的急迫需求.本研究利用等离子体处理技术可降解乙腈水溶液中的DON,并通过胶体金定量试纸条和液质联用仪进行了分析.通过高分辨质谱测定分析,推导出12种降解产物.进一步对去环氧基降解产物质谱碎片峰进行匹配并推导其裂解途径.结果表明...     

Effect of Succinylation on the Proteolysis of Food Proteins

Casein, bovine serum albumin and soy globulin were succinylated and used as substrates, in both forms, for initial velocity studies of proteolysis by α-chymotrypsin and pepsin. Succinylation resulted in modification of at least 91% of the free amine groups of the proteins. Proteolysis was determined by fluorometrically monitoring the appearance of amine groups. Kinetic constants were estimated by the direct equation plot using FORTRAN programs. Succinylation enhanced the initial proteolysis of all substrates by either enzyme as evidenced by an increased maximum velocity and decreased Michaelis constant for the modified substrates. Modification of casein caused the most pronounced differences in rates of proteolysis, resulting in the largest change in kinetic constants for pepsin and the smallest change for α-chymotrypsin.     

琼脂对Komagataeibacter xylinus自发变异的控制

本文研究Komagataeibacter xylinus静态及动态培养中琼脂对其自发变异和细菌纤维素（Bacterial Cellulose,BC）产量及结构的影响。采用涂布法对变异菌率,称重法对纤维素产量以及傅里叶变换红外光谱法和粘度法分别对BC的结晶度和聚合度进行分析,并采用分光光度法对纤维素酶活力测定。结果显示,静态和动态培养中皆出现变异菌,BC产量分别为0.16和0.09 g/L;而静态培养中添加0.05%琼脂和动态培养中添加0.10%琼脂的培养液中没有分离到变异菌株,BC产量分别提高至0.38和0.34 g/L。0.05%琼脂静态培养液连续转接九次过程中没有分离到变异菌株,0.10%琼脂动态培养液连续转接至第二次时,出现变异菌株。以未添加琼脂静态培养为对照,静态培养中,0.05%琼脂使BC的聚合度和结晶度分别下降4.0%和12.9%,动态培养中,0.10%琼脂使BC的结晶度下降了51.2%。尽管纤维素酶活力不受培养方式和琼脂的影响,但动态条件下,因琼脂显著下降了BC的结晶度,纤维素酶易水解BC,因此,BC的聚合度下降了42.2%。     

超声波催陈新醋的工艺研究

该研究以食醋中总酯含量为响应值,在单因素试验基础上,通过响应面法优化超声波催陈新醋的工艺,并考察超声波对食醋理化指标的影响,同时采用顶空-固相微萃取（HS-SPME）和气质联用（GC-MS）法对新醋与超声波处理后食醋的挥发性成分进行测定和对比。结果表明,最优超声波催陈工艺条件为超声波处理时间137 min、乙醇添加量0.65%（V/V）、超声波处理温度40 ℃。在此最优条件下,食醋中的总酯含量为13.75 g/L,比原醋提高了50%,与自然陈酿5个月的食醋相当,总酸、氨基酸态氮及还原糖含量均降低,且色泽深而澄清,醋味柔和浓郁;新醋经超声波催陈后,总酸的相对含量减少了24.84%,酯类物质相对含量增加了9.88%,2,3,5,6-四甲基吡嗪的相对含量增加了5.38%,为改善传统食醋的陈酿方法提供了理论依据。     

Gaschromatographic Analysis of the Substitution Pattern of Hydroxyethyl Starch

The substitution parameters, molar substitution (MS) and degree of substitution (DS) for commercial O-(2-hydroxyethyl) derivatives (HES) of starch have been determined by measuring the relative amounts of glucose and its O-(2-hydroxyethyl) derivatives in hydrolysates of HES. The monomers in the hydrolysate were estimated by conversion to per-O-ethylated alditols which were analysed by gas chromatography. The identity of the monosubstituted derivatives was confirmed by their mass spectra and by synthesis of model compounds. Disubstituted monomers were identified by their mass spectra while trisubstituted components were not separated.     

木聚糖酶在玉米原料酒精发酵中的应用研究

探讨了木聚糖酶对玉米原料酒精发酵的影响.经优化后木聚糖酶的最适使用工艺为:木聚糖酶在发酵开始时加入,添加量为170U/g,料水比为1:2.5,初始pH值为自然.与对照组相比,原料出酒率提高5.93%,发酵周期缩短了12h,表明木聚糖酶对玉米原料酒精发酵有明显的促进作用.