Hypolipidaemic effects of dietary whole soybean curd (jeondubu) in rats

BACKGROUND: The characteristic of whole soybean curd is that it includes the soybean residue that is discarded as waste in the manufacture of usual soybean curd (known as tofu). In this study the effect of dietary whole soybean curd on lipid profiles in rats was compared with that of usual soybean curd. Rats were fed for 4 weeks with diets differing only in the source of protein, namely casein, whole soybean curd or usual soybean curd. RESULTS: There were no significant differences in growth parameters due to diet differences. However, the two groups fed with curds had significantly lower levels of serum cholesterol and triglyceride than the group fed with casein, the greatest reduction in lipid profiles being observed in the group fed with whole soybean curd. The serum high‐density lipoprotein cholesterol/total cholesterol ratio was higher in rats fed with whole soybean curd. CONCLUSION: The results suggest the possibility that whole soybean curd may have more beneficial effects in controlling serum lipid profiles than usual soybean curd that is normally consumed. Copyright © 2011 Society of Chemical Industry     

微拟球藻活性成分分离及抑菌活性研究

海洋微藻因其特殊的生存环境使其可以合成高附加值的代谢产物而成为天然抗菌素筛选的重要途径。采用纸片法对微拟球藻的不同极性提取物及其分离组分进行抗4种病原菌活性研究,并采用柱层析和薄层层析方法对石油醚提取物进行进一步的分离纯化及成分分析,结果显示:6种提取物在较高的受试浓度下对大肠杆菌都呈现出较强的抑菌活性,此外,乙醇相提取物对其它3种受试菌都表现出明显的抑制效果,而石油醚相对铜绿假单胞菌有一定的抑菌活性,乙酸乙酯相和正丁醇相提取物对白色念珠菌有明显的抑菌效果。石油醚相提取物进一步分离获得3个纯度较高的组分,成分分析结果显示PEⅢ-5-1为叶绿素类化合物;PEⅤ-1中酮类物质含量最多,占55.74%,其次是酯类;PEⅤ-2中含量最多的是酯类,占50.54%;其次是酮类和有机酸类。     

Physicochemical properties of whole soybean curd prepared by microbial transglutaminase

Whole soybean curd (WSC) was manufactured using micronized full-fat soybean (MFS) powder and microbial transglutaminase (TGase). The WSC prepared with 15% MFS had typical soybean curd texture with a hardness of 513 dyne/cm². It was confirmed that 7S and 11S protein fractions as major soy proteins disappeared in SDS-PAGE. Also, WSC prepared with 15% MFS and 10% TGase had excellent textural properties with a hardness of 645 dyne/cm² and springiness of 0.98. Addition of 0.5% gelatin in WSC prepared with 15% MFS and 5% TGase resulted in higher hardness (708 dyne/cm²) and springiness (0.98), as well as the highest values of G′ and G″. The surface properties of WSC were observed using a SEM, indicating the interrelationship of higher hardness and compact protein network filled with small cells. It was concluded that WSC prepared after heat treatment of 15% MFS at 95°C for 5 min, followed by an enzyme reaction with 10% TGase for 1 h, had more enhanced hardness and springiness than commercial WSC. Despite the addition of 5% TGase, WSC with improved textural properties can be manufactured by the fortification of 0.5% gelatin.     

响应面法优化全豆豆腐凝固剂配方的研究

利用干法工艺制备全豆豆腐,在单因素实验基础上,选取葡萄糖酸-δ-内酯(GDL)、氯化镁(MgCl_2)和谷氨酰胺转氨酶(TG酶)添加量作为影响因素,以全豆豆腐凝胶强度和感官评分作为指标,进行Box-Behnken实验,建立二次多项式回归模型,用于全豆豆腐最佳凝固剂配方的优化。结果表明,GDL添加量对全豆豆腐凝胶强度的影响最大,TG酶添加量的影响最小;而感官评分二次多项式回归模型不显著。干法工艺制备全豆豆腐的凝固剂最优配方为:GDL添加量0.5%,MgCl_2添加量0.07%,TG酶添加量0.02%。在该条件下所制得的全豆豆腐凝胶强度为185.956 g;微观结构表现为致密、均匀和相互交联的凝胶网状结构。     

黑曲霉全豆腐乳的制备及其营养特性研究

为解决豆制品企业豆渣囤积易腐败和低值化问题,并提高腐乳产率,该研究以黑曲霉（Aspergillus niger）发酵豆渣为原料,将其回填至豆浆中,制作成黑曲霉全豆腐乳,按照腐乳生产标准进行检测,并与传统腐乳的营养特性进行对比。结果表明：黑曲霉全豆腐乳符合腐乳生产标准,通过扫描电镜观察,黑曲霉全豆腐乳无明显纤维结构,且表现出较好的质构特征;对比传统腐乳,黑曲霉全豆腐乳出品率提高8.43%;持水性降低3.22%;总膳食纤维含量提高25.14%;总皂苷降低48.44%;大豆异黄酮降低45.03%;蛋白体外消化率提高13.02%;黑曲霉全豆腐乳共检出挥发性风味物质39种和17种氨基酸,总氨基酸含量为26.58 g/100 g。该研究对豆渣的综合利用提供了新途径,提高了膳食纤维含量和出品率,降低了成本,具有进一步产业化的潜力。     

Iron enrichment of whole potato tuber by vacuum impregnation

The effect of vacuum time, restoration time, steam-cooking and storage at 4 °C on the iron content of vacuum-impregnated (VI) whole potato was evaluated. Whole potato tubers were immersed in a 0.4 g/100 g iron (ferric pyrophosphate) solution. Vacuum pressure of 1000 Pa was applied for 0–120 min, and atmospheric pressure restoration for 0–4 h. The result indicated that the iron content of VI potatoes increased with vacuum and restoration time; 1 h vacuum-treatment potatoes provided 6.4 times higher iron content compared to raw potatoes, and 3 h restoration time supplied 6.4 times higher iron content (>4.1 mg/100 g fr.wt.) compared to raw potatoes. Moreover, VI-cooked unpeeled or peeled potatoes had 6 times higher iron content than un-VI-cooked unpeeled or peeled potatoes. European daily potato consumption (260 g) of the VI-cooked unpeeled and peeled potatoes provided adult men with 93–104% and 67–90% of the recommended daily allowance (RDA) of iron, respectively. Also, the daily potato consumption of the unpeeled and peeled potatoes could supply adult women with 43–48% and 31–41% of the RDA, respectively. This study indicated that VI treatment of whole potato was useful for enriching the iron content.     

Ascorbic acid enrichment of whole potato tuber by vacuum-impregnation

The aim of this study was to evaluate the use of vacuum-impregnation (VI) for enriching the ascorbic acid content of whole potatoes. Whole potatoes were immersed in a 10% ascorbic acid (AA) solution. A vacuum pressure of 70 cm Hg was applied for 0–60 min, following atmospheric pressure restoration for 3 h, while samples remained in the VI solution. AA concentrations of potatoes were measured using HPLC. The effects of cooking and storage time in subsets of the fortified samples were also evaluated. Results indicated that the AA concentration of whole potatoes increased with vacuum time (max 150 mg/100 g fr. wt.). In addition, a steam-cooking study showed that 100 g of the 25 min steam-cooked VI potatoes could provide adults with 90–100% of the recommended daily allowance of AA (100 mg). The storage study showed that VI whole potatoes had a relatively high AA concentration (50 mg/100 g fr. wt.), even at 14 days of storage at 4 °C. This study indicated that VI treatment of whole potatoes was useful for enriching the AA content.     

Pathway-based genome-wide association analysis of milk coagulation properties,curd firmness,cheese yield,and curd nutrient recovery in dairy cattle

It is becoming common to complement genome-wide association studies (GWAS) with gene-set enrichment analysis to deepen the understanding of the biological pathways affecting quantitative traits. Our objective was to conduct a gene ontology and pathway-based analysis to identify possible biological mechanisms involved in the regulation of bovine milk technological traits: coagulation properties, curd firmness modeling, individual cheese yield (CY), and milk nutrient recovery into the curd (REC) or whey loss traits. Results from 2 previous GWAS studies using 1,011 cows genotyped for 50k single nucleotide polymorphisms were used. Overall, the phenotypes analyzed consisted of 3 traditional milk coagulation property measures [RCT: rennet coagulation time defined as the time (min) from addition of enzyme to the beginning of coagulation; k₂₀: the interval (min) from RCT to the time at which a curd firmness of 20 mm is attained; a₃₀: a measure of the extent of curd firmness (mm) 30 min after coagulant addition], 6 curd firmness modeling traits [RCT_eq: RCT estimated through the CF equation (min); CF_P: potential asymptotic curd firmness (mm); k_CF: curd-firming rate constant (% × min^?1); k_SR: syneresis rate constant (% × min^?1); CF_max: maximum curd firmness (mm); and t_max: time to CF_max (min)], 3 individual CY-related traits expressing the weight of fresh curd (%CY_CURD), curd solids (%CY_SOLIDS), and curd moisture (%CY_WATER) as a percentage of weight of milk processed and 4 milk nutrient and energy recoveries in the curd (REC_FAT, REC_PROTEIN, REC_SOLIDS, and REC_ENERGY calculated as the % ratio between the nutrient in curd and the corresponding nutrient in processed milk), milk pH, and protein percentage. Each trait was analyzed separately. In total, 13,269 annotated genes were used in the analysis. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway databases were queried for enrichment analyses. Overall, 21 Gene Ontology and 17 Kyoto Encyclopedia of Genes and Genomes categories were significantly associated (false discovery rate at 5%) with 7 traits (RCT, RCT_eq, k_CF, %CY_SOLIDS, REC_FAT, REC_SOLIDS, and REC_ENERGY), with some being in common between traits. The significantly enriched categories included calcium signaling pathway, salivary secretion, metabolic pathways, carbohydrate digestion and absorption, the tight junction and the phosphatidylinositol pathways, as well as pathways related to the bovine mammary gland health status, and contained a total of 150 genes spanning all chromosomes but 9, 20, and 27. This study provided new insights into the regulation of bovine milk coagulation and cheese ability that were not captured by the GWAS.     

腐乳生产技术(六)

5　腐乳生产用微生物5.1　微生物的特点及作用5.1 .1　微生物的特点在生物界中有一大类体形极小、用肉眼看不见必须借助显微镜或放大镜才能看清楚的生物体 ,称为“微生物”。他们个体通常是单细胞或简单的多细胞 ,构造也极简单。微生物在自然界中具有分布广、种类多、体积小、繁殖快、易变异等特性。5.1 .1 .1　微生物分布广、种类多在土壤、河流、空气、平原、高山、深海、温带、热带、寒带、油井、矿山、盐湖、植物、动物和人体内外 ,都有微生物存在着。特别土壤是微生物最集中的地方 ,因为土壤营养丰富 ,水分适宜 ,温度变化不大等条件 ,…     

腐乳生产技术(十一)

王瑞芝10　腐乳生产下脚料的综合利用　　在腐乳生产过程中,要产出大量的下脚料及废液等。主要来自三个工序:其中有磨豆分离出来的豆渣产品,制坯操作中豆浆凝固沉淀后和压榨出来的黄泔水及毛坯腌制中析出的咸卤水(俗称毛花卤)等,均作废料和废液处理。从目前国内情况来看,这些下脚料及废液利用量极少,大部分没有得到充分利用。经调查,多数企业是这样处理的:豆渣主要售于养猪业、养牛业、养鱼业及养虾业作饲料用,也有少部分地区将豆渣废弃。对黄泔水除少数企业作为白地霉培养基生产酵母及其他利用外,大约有90%企业作为废液排放掉。腌制出来的…     

腐乳生产技术(八)

1　制造原理酒酿卤是酿造乳腐的重要卤汤,以糯米为原料,通过根霉及酵母中各种酶的作用,将淀粉分解为糊精、糖类及酒精等物质,成为甜酒酿卤,它的特点是糖份高,浓度厚,有一定的酒精度和浓郁的甜香味。酒酿卤是腐乳的主要辅料,用酒酿卤酿制腐乳风味好,适合群众口味,同时产品成本也低。在江南和上海等地也有人自制,一般有二种制法。第一种甜酒酿制造时间短,只要保持适当温度,48h即可成熟,这种酒酿还可糟肉、糟鸡、糟鱼、糟蛋、制作酒酿圆子等,是适用多种食品的佳品。另一种是弃糟的酒酿卤,发酵期长,一般约8天左右,其酒精度高于上述酒酿。在江渐…     

Moisture sorption characteristics of curd (Indian yogurt) powder

The moisture sorption behaviour of curd (Indian yogurt) powder was studied at 20, 30, 40 and 50°C for water activity ranging from 0.07 to 0.85. GAB, BET, Henderson, Halsey, Chung & Pfost, Smith, Oswin and Peleg models were applied to analyse the data. Estimated parameters and fitting ability for sorption models were evaluated. The GAB model showed the best fit to the sorption data of curd powder at 20, 30 and 40°C, and the Peleg model fitted well at 50°C.     

腐乳生产技术(九)

8　腐乳后期发酵8.1　后期发酵变化乳腐后期发酵,主要是借助毛霉中的蛋白酶使蛋白质水解,成为各级肽类和氨基酸,赋予腐乳以细腻和鲜味及形成特有的色、香味、态等特色。在后期发酵之前,将腐乳毛坯加食盐腌制、使腐乳坯在腌制过程中渗透盐份,析出水份,把坯内含有70%左右水份降为54%左右,使坯体收缩变得较硬。在腌制过程中,要控制一定的用盐量和腌制时间。食盐用量过多和时间过长,使蛋白质凝胶脱水过度、俗称“腌煞坯”,造成坯子过硬,不利于蛋白酶的作用其次由于食盐浓度过高,蛋白酶也遭受变性,酶活下降作用减退,发酵中难以使坯身复原,内部分…     

腐乳生产技术(十二)

二级种子培养。在二级种子罐中,加入1.2t黄浆水,加氨水调pH4.4～4.8,将一级种子分半接入,接种量为8%,进行通风培养,温度为28～31℃,pH值用氨水调节为4.4～4.8,培养10～12h,其中流加糖液,维持还原糖0.5%～1.0%,每小时测残糖量、巴林浓度、pH值,并取样观察酵母繁殖情况及有无杂菌等。商品酵母培养。商品酵母是在二个容积分别为20t,28t的培养罐中轮流培养,先在罐中加入11t黄浆水,调节pH同上,接入二级种子1400kg,维持温度28～34℃,通风培养7～10h,在培养过程中,流加糖液、氨水、磷酸、培养液维持还原糖0.3%～0.4%,残糖在0.20%左右为好。在…     

腐乳生产技术(四)

4 1 4 1　豆浆浓度豆浆浓度是指豆浆中的大豆蛋白质的含量。豆浆浓度低 ,其有效成分呈明显的解离状态 ,蛋白质的疏水性就强 ,加入凝固剂后 ,使蛋白质过度收缩 ,形成细小豆腐花 ,而细小豆腐花浮在黄泔水当中 ,不能组成较好的网状结构 ,凝固物结合性差 ,凝固组织结构分散 ,难以制成豆腐坯 ;同时细小的豆腐脑极多 ,这些细小的豆腐花会随水流失。豆浆浓度太高 ,造成点浆困难 ,下卤时上下翻动不均匀 ,使凝固剂作用不完全 ,也容易形成大块豆腐脑 ,对制坯带来不便 ,导致豆浆损失 ,影响出品率。“浆稀点不嫩 ,浆稠点不老。”这是工人师傅们长期生…     

腐乳生产技术(五)

4 1 7　蹲脑蹲脑又称为涨浆或养花 ,是大豆蛋白质凝固过程的继续。点浆操作结束后 ,蛋白质与凝固剂的凝固过程仍在继续进行 ,蛋白质网状结构尚不牢固 ,只有经过一段时间的静置 ,凝固才能完成 ,组织结构才能稳固。蹲脑过程宜静不宜动 ,否则 ,已经形成的凝胶网状结构会因振动而破坏 ,使其内在组织裂隙 ,凝固无力 ,外形不整 ,特别是在加工小块型的腐乳时表现更为明显。在点浆时 ,豆浆的搅拌速度和时间直接关系着凝固效果。搅拌得越剧烈 ,凝固剂的使用量越少 ,凝固的速度越快。搅拌速度慢 ,凝固剂的使用量就多 ,凝固的速度缓慢。搅拌的速度要视…     

腐乳生产技术(七)

6　腐乳前期发酵6 .1　发酵机理在酿造腐乳过程中 ,有物理化学和生物化学变化 ,整个过程又分为前期发酵和后期发酵两个阶段。前期发酵 (亦称发花 ) ,主要是将毛霉菌 (或根霉菌 )接种于豆腐坯上 ,让其在蛋白质 (豆腐坯 )培养基上充分繁殖 ,使豆腐坯表面生成一层白色细柔的菌膜 ,同时分泌大量蛋白酶 ,便于后期发酵使蛋白质缓慢水解。在前期菌丝生长阶段 ,豆腐坯的蛋白质已开始被蛋白酶水解为水溶性蛋白质(胚和胨 )。豆腐坯的水溶性蛋白质含量为3.6 1 %、而通过前期发酵后的水溶性蛋白质含量达 55.54%。前期发酵主要是培养毛霉菌过程 ,其目的归…     

The viscoelastic properties of soybean curd (tofu) as affected by soymilk concentration and type of coagulant

The viscoelastic properties of different types of tofu were investigated. Soymilk concentrations were 5, 6, 7, 8 and 9%. Coagulants used were 30 mm CaSO₄ or 30 mm glucono‐delta‐lactone (GDL). As the concentration of soymilk was increased viscosity and handling difficulties increased. A high concentration of soymilk in tofu gave a high break stress and produced hard tofu. The four‐element Burgers model fitted the creep behaviour and both viscous and elastic parameters could be acquired from model analysis, reflecting changes in elasticity and viscosity of tofu. The constant viscous parameter in the model increased with increasing soymilk concentration. The viscous parameters of viscoelastic materials like tofu gel, obtained from small deformation tests, seemed to correlate, to some extent, with the break stress obtained from large deformation tests. For hard tofu production increasing the soymilk concentration within a certain range and the partial replacement of calcium sulphate coagulant by GDL could be effective options.     

Processing whole cottonseed moderates fatty acid metabolism and improves performance by dairy cows

Pelleting cottonseed (CS) improves handling characteristics. Our objectives were to determine whether increasing the particle size of the CS pellet or dilution of a smaller pellet with delinted CS would limit the rate of CS oil release to optimize digestibility of fatty acids (FA) and fiber while maintaining milk fat production. In a 5 × 5 Latin square design with 3-wk periods, 5 rumen-cannulated cows were fed 1) control with CS hulls (CSH) and CS meal plus tallow and Ca soaps of FA, 2) whole CS (WCS), 3) small CS pellets (SP; 0.44-cm die diameter), 4) larger CS pellets (LP; 0.52-cm die diameter), or 5) a blend of SP plus partially delinted CS (SPD). Diets contained 39.6% concentrate, 14.4% CS, and 46% forage (40:60, alfalfa hay:corn silage) on a DM basis and were balanced to have similar concentrations of CS protein, CS fiber, and total fat. In a production trial, dietary treatments were 1) WCS control, 2) LP, 3) SPD, and 4) SPD fed at 90%. Sixty cows averaging 105 d in milk were fed the WCS diet for 2 wk and then assigned to one of the 4 diets for 12 wk. Total tract digestibility of NDF was unaffected, but N digestibility was lower for SPD than for other treatments. Fatty acid digestibility was higher for SP and LP (82.6 and 82.3%) than for CSH or SPD treatments (78.8 and 75.3%), and WCS was intermediate (81.1%). The trans-11 C_18:1 from cows fed SP and LP (6.58 and 6.24% of total milk FA) was greater than that from cows fed CSH, WCS, and SPD (3.23, 3.79, and 3.97%). The trans-10 C_18:1 in milk fat from SP and LP (0.508 and 0.511%) was higher than that in WCS and SPD diets (0.316 and 0.295%); CSH was intermediate (0.429%). Using passage rates estimated from the NRC, disappearance of total FA in situ was estimated to be 17.7, 44.2, 46.6, and 35.0% for WCS, SP, LP, and SPD, respectively. In the production trial, a diet × week interaction was explained by a trend for progressively greater milk production for SPD and SPD90 than for WCS or LP. Milk fat was lower for LP (2.74%) and SPD90 (2.85%) than for WCS or SPD (3.07 and 3.08%). The fat yield was lower for LP than for SPD (1.09 and 1.30 kg/d); WCS and SPD90 were intermediate (1.23 and 1.21 kg/d). Although having a lower FA digestibility, SPD appeared to minimize negative effects of free oil from SP in the rumen, explaining higher DMI and milk production compared with WCS or LP.     

The effect of roasting nonlinted whole cottonseed on milk production by dairy cows

This study was conducted to examine the effect of roasting nonlinted whole cottonseed on ruminal crude protein (CP) degradability and performance in high-yielding dairy cows. Multiparous Israeli Holstein-Friesian cows (parity average 2.5+/-1.5; n = 132) with 571+/-65 kg of body weight (BW), 107+/-48 d in milk (DIM), and 37+/-5.8 kg of milk yield/d were used in the study. Cows were divided into two dietary treatment groups according to their BW, DIM, and milk production. The two diets were similar in CP, net energy for lactation, and neutral detergent fiber content [17%, 1.74 Mcal/kg, and 30% on a dry matter (DM) basis] and included either 15% (on a DM basis) whole cottonseed or roasted whole cottonseed. Ruminal effective degradability of CP, organic matter (OM), and ether extract (EE) decreased 14, 11, and 10%, respectively, compared to whole cottonseed. Total tract digestibilities of CP and EE were similar for both treatments and averaged 57 and 59%, respectively. However, DM and OM digestibilities were 6 and 5% higher in cows offered roasted whole cottonseed relative to those fed whole cottonseed diet. The inclusion of roasted whole cottonseed in the ration decreased ruminal ammonia and blood urea N concentration by 12% compared with diet with the raw whole cottonseed. Milk production, milk fat content, and production, and milk protein yield increased when roasted, nonlinted whole cottonseed was included in the diet. Milk protein content was similar for both treatments, averaging 2.92%.