EFFECT OF SOYBEAN STORAGE ON TOFU AND SOYMILK PRODUCTION1

Century 84 and Century -L₂L₃ (lacking lipoxygenase isozymes 2 and 3) near isogenic soybean varieties were stored at five temperature and relative humidity conditions for up to three months. At one-month intervals, soybeans were retrieved from storage and processed into soymilk and tofu. Chemical and physical characteristics of the soybeans, soymilk, and tofu were analyzed. In general, soybean storage above 25C and 50% relative humidity adversely affected the characteristics of the soymilk (reduced pH and solids content) and tofu (decreased yield and moisture content, and darker color) produced. Century -L₂L₃ soybeans were more resistant to changes during adverse storage than were Century 84 soybeans.     

EFFECT OF MANGO PULP AND SOYMILK FORTIFICATION ON THE TEXTURE PROFILE OF SET YOGHURT MADE FROM BUFFALO MILK

The effect of the fat content in buffalo milk and proportions of buffalo milk, soymilk and mango pulp on textural characteristics of mango soy fortified yoghurt (MSFY) is reported. The TA-XT2 Texture Analyzer was used to measure the textural characteristics of MSFY prepared from blends containing varying proportions of buffalo milk (varying fat content), soymilk (8.2% total solids) and mango pulp (18% total solids). Texture profile data were used to develop regression models for dependent variables—hardness (HD), cohesiveness (CO), adhesiveness (AD), springiness (SP) and gumminess (GU), which were used to optimize the blend formula. The optimized values are 2.95% fat content in buffalo milk, 14.7% soymilk and 7.2% mango pulp in the blend for obtaining MSFY having textural characteristics similar to those of yoghurt having 6% fat. The MSFY prepared using optimized blend had HD (108 - 112 g), CO (0.41 - 0.42), AD (- 70.3 to - 72.9 g.s), SP (0.93 - 0.96) and GU (45.05 - 46.38 g).     

Frozen Wild Blueberry-Tofu-Soymilk Desserts

Both wild (lowbush) blueberries (Vaccinium angustifolium Ait.) and soybeans (Glycine max L.) possess a variety of antioxidants, and both foods appear to have multiple health benefits. Our objectives were to identify whether wild blueberry juice concentrate was more acceptable than puree in frozen desserts with a soy milk‐tofu base; to determine whether fat‐free products were as acceptable as those with 10% added fat; and to compare several levels of blueberry juice concentrate. Four frozen dessert formulations were prepared in duplicate from soy milk, silken tofu, sucrose, stabilizer, BJC or puree, soybean oil or polydextrose, sweetened dried blueberries, salt, and lemon juice. Samples were assayed for total anthocyanins, antioxidant activity using the DPPH method, color, overrun, and solids. Fifty‐five persons evaluated the samples using a 9‐point hedonic scale for color, flavor, texture, and overall acceptability. Samples containing blueberry juice concentrate were darker and less blue. Anthocyanin levels were highest in the puree sample and the fat‐free product with 7.8% blueberry juice concentrate. However, antioxidant activity was highest (28 Trolox equivalents per gram) in the samples made with soybean oil and 7.4% blueberry juice concentrate. The puree formulation received higher hedonic scores than did the low‐fat blueberry juice concentrate formulations. The puree formulation received overall acceptability scores of like very much or like extremely by 45% of the consumers. These findings may aid processors in defining potential formulations that combine 2 healthful food ingredients.     

大豆不同前处理方式对豆浆品质的影响

为探讨大豆不同前处理方式对豆浆品质的影响,选择5 种前处理方式,对所制得豆浆的感官品质、色泽、稳定性、主要营养成分及抗营养因子含量进行对比分析。结果表明：大豆不同前处理方式对豆浆品质有不同的影响。干豆直接制浆虽方便快捷,但所得豆浆品质较差,其感官品质、稳定性均差于浸泡大豆,且主要营养成分如蛋白质、多糖得率低,抗营养因子含量高;高温高压蒸煮大豆制浆,其感官品质、稳定性及抗营养因子的去除效果均差于浸泡大豆,且色泽偏暗,蛋白质损失严重,含量低于干豆制浆;与干豆直接制浆相比,浸泡处理大豆可明显改善豆浆感官品质及其稳定性,且其蛋白质、可溶性固形物、多糖含量显著提高（P＜0.05）,抗营养因子含量显著下降（P＜0.05）;免浸泡豆和NaHCO3溶液泡豆制得豆浆色泽最亮,综合品质最好。     

Effects of Milk Solids Content on Consumption of Milk

Strong interest continues for higher solids-not-fat standards for whole, lowfat, and skim milk than those currently established by the Food and Drug Administration for milk in interstate commerce. This paper traces the implications of establishing new national fluid milk standards identical to the current high standards in California. The greatest change in product composition implied by the adoption of the California standards would be in lowfat milk, where the solids-not-fat standard would rise from 8.25 to 10.0%. Whole and skim milks’ composition would be less dramatically affected.Fortification costs are estimated at 3¢/.5 gal (1.89 L) for whole milk, about 5¢ for lowfat milks, and about 1.5¢ for skim milk. Retail prices are projected to rise 3 to 5% across the fluid product line. Assuming no change in consumer preferences, fluid milk sales are estimated to drop 1.2 to 5.1% nationwide upon adoption of the California solids standards (the percentage drop dependent upon the responsiveness of consumers to price changes for fluid milk). Total sales of solids-not-fat would increase 21 to 184 million lb (19.52 to 83.46 million kg) annually under higher solids standards, which is not enough to affect significantly the current supply-demand imbalance in the dairy industry.     

Effect of partial substitution of cow's milk with soymilk on yield and quality attributes of West African soft cheese

Warankasi , a soft unripened cheese, was made from milk containing up to 20% soymilk. The best cheeses were obtained from soymilk prepared by grinding in boiling water soybeans that had been preheated by dipping in hot water, 95–100°C, for 15–20 sec. Cheeses containing soymilk were comparable with controls made from whole cow's milk in yield, nitrogen and fat content, and flavour. Cheeses with up to 10% soymilk had a slight brownish colour, but overall acceptability was not impaired, relative to controls. Cheeses with 20% soymilk were acceptable although inferior to controls.     

Production and Textural Properties of Soy-Cheese Whey Curd

Soy-cheese whey curd was prepared by mixing soymilk and cheese whey with the addition of glucono-delta-lactone (GDL) to coagulate the proteins. Three soymilk concentrations, 6:1, 8:1 and 10:1 (water:bean, v/w), and four cheese whey levels, 3%, 4.5%, 5.25% and 6% (w/v), were used. Heating the GDL treated soy-cheese whey milk in a hot water bath at 85°C for 25 min consistently produced a smooth and compact. curd without syneresis. Textural properties of the curd were tested by an Instron machine. Five parameters-stiffness, bioyield point, firmness, relaxation and plasticity—were determined. Among these, only stiffness and firmness could be used as the textural parameters for the curd.     

QUALITY AND SWEETNESS OF BAKED CUSTARDS MADE WITH LACTOSE-REDUCED MILKS

Lactose concentrations of lactose-reduced and hydrolyzed lactose-reduced milk (12.1, 4.9 g/L milk, respectively) were significantly lower (p < .05) than the lactose concentration in the control (1% milkfat) milk (38.4 g/L milk). Lactose concentrations in custard mixes made from lactose-reduced and hydrolyzed lactose-reduced milks (6.8, 3.2 g/L mix, respectively) were significantly lower (p < .05) than the lactose concentration in the control custard mix made from 1% milk (29.9 g/L mix). Consumers ranked the lactose-reduced milk and the hydrolyzed lactose-reduced milk significantly higher in sweetness than the control milk. No differences in sweetness between the control, lactose-reduced, and hydrolyzed lactose-reduced baked custards were perceived. Firmness, color, syneresis, and water activity did not differ (p > .05) among the control, lactose-reduced, and hydrolyzed lactose-reduced baked custards.     

EFFECT OF SOLID CONTENT AND SUGAR COMBINATIONS ON THE QUALITY OF SOYMILK-BASED YOGURT

A research to evaluate the effect of two levels of solids and two sugar combinations in the quality of a soymilk yogurt-type food was carried out. Yogurts were elaborated by inoculating lactic cultures ( Lactobacillus dellbruckii spp. bulgaricus and Streptococcus salivarius spp. thermophilus ) into soymilk with 8% and 11% solid levels and glucose/sucrose and glucose/fructose mixtures. Also, a control treatment with cow milk was prepared. Yogurts were analyzed after two days of preparation for their chemical (protein, lipids, titrable acidity and pH), physical (syneresis and viscosity) and sensory characteristics (quality and acceptability). Protein content of soymilk based yogurts ranged between 3.56 and 4.45 g/100 g. The higher titrable acidities (0.66% and 0.63% lactic acid) were shown by treatments with higher solids level, which also shown the lowest syneresis. All soymilk yogurts were yellowier than the control. The highest sensory acceptability was for the 8% solids treatment enriched with glucose and sucrose.

PRACTICAL APPLICATIONS

There are an increasing number of people suffering of lactose intolerance, which need an alternative product to milk. Besides, some people have adopted a strictly vegetarian way of life. Soymilk has been used for a long time by this part of the population; however, it usually has a beany flavor, which can cause some rejection among occidental consumers. A fermented product from soymilk, such as soymilk yogurt, may offer a good alternative for those people. In soymilk production it is necessary to carefully adjust the amount of solids and the sugar used in fermentation in order to obtain a well accepted commercial product. Soy yogurt could be used to formulate a number of different new products like desserts, high fiber yogurt, fruit-added yogurt and so on.     

红紫芽熟茶适制性及渥堆发酵过程品质变化研究

目的 研究大叶种特异性品种红紫芽熟茶适制性及渥堆发酵过程中品质变化规律。方法 以红紫芽晒青茶为原料,分别以气相色谱-质谱法(gas chromatography-mass spectrometry, GC-MS)、电子鼻、色差分析结合感官审评方法研究红紫芽熟茶适制性及渥堆发酵过程中品质变化。结果 红紫芽晒青茶共鉴定6大类28种香气物质,红紫芽出堆样共鉴定出9大类46种香气物质, Loading结果表明, 10个传感器中就有5个传感器(R8、R6、R10、R7和R9)对茶叶香气的响应明显,对区分贡献率最大,香气分析结果表明红紫芽叶制成熟茶香气物质丰富。随着翻堆序数增加, L~*和?L值总体呈下降趋势, a~*和?a值总体呈增加趋势b~*及?b值随着翻堆序数增加呈先增加后下降趋势,表明随着发酵进行,茶汤明亮度降低,茶汤变红变深,这与感官评价结果一致。随着渥堆序数增加,总儿茶素、茶多酚及氨基酸含量呈递减趋势,出堆样氨基酸、茶多酚含量低于晒青原料(P<0.05),水浸出物含量高于晒青原料(P<0.05),每一次翻堆样咖啡碱的含量变化幅度也不大(P>0.05)。感官审评结果表明...     

Detection and Control of Soymilk Astringency

Soymilk was made less astringent by the addition of skimmed cow's milk (SCM), CaSO₄ or citric acid. The additions of CaSO₄ and citric acid were not sufficient to cause visible separation of soymilk solids, but there was some difference in mouthfeel due to the additions. Warm temperatures (65°C) of the soymilk resulted in a loss of astringency compared to sensory evaluation at room temperature or 4°C. Analyses for total polyphenols showed statistically significant decreases in apparent polyphenol content per gram of soymilk solids with the first level of addition of SCM, CaSO₄, or citric acid but not with subsequent additions.     

无氧磨浆工艺对腐竹品质的影响

分别采用常规磨浆和无氧磨浆两种磨浆工艺生产豆浆,考察了二者成分及蛋白质组成的差异,并分析了以两种豆浆制备的腐竹的得率、成分组成、色泽、延伸率和耐煮性的差异。结果表明:两种磨浆工艺生产的豆浆的成分组成及蛋白质组成无明显区别,SDS-PAGE结果发现,无氧豆浆的氧化程度较低;两种豆浆生产的腐竹得率相近,但腐竹中的蛋白质含量变化趋势存在显著差异,同时无氧磨浆条件制备的腐竹中的脂肪含量普遍较高;无氧磨浆条件下制备的腐竹的色泽均一性较好,呈亮黄色,而常规磨浆条件下制备的腐竹褐变现象严重;无氧腐竹的延伸率和耐煮性较好,分别较常规腐竹提高35%和25%。     

Simultaneous Curdling of Soy/Cow's Milk Blends with Rennet and Calcium or Magnesium Sulfate, Utilizing Soymilk Prepared from Soybeans or Full-Fat Soy Flour

Mixed soy/cow's milk curds were prepared by simultaneous curdling of soy/cow's milk blends, utilizing rennet as cow's milk coagulant and calcium or magnesium sulfate as soymilk coagulant. The method produced curds of similar characteristics (compactness and yield), whether soymilk prepared from soybeans or full-fat soy flour was used. The effect of a number of process variables on curd characteristics was studied, utilizing a fractional factorial design. Generally, large changes in process variables (23 – 230%) produced relatively small charges in curd characteristics (1 – 16%). Protein contents of raw materials and proximate chemical analyses of pure and mixed milk curds, prepared under conditions yielding maximum curd compactness were determined. Protein recoveries in curd preparation were calculated.     

黑甜玉米酸奶冰淇淋的研制

对营养型黑甜玉米酸奶冰淇淋进行了配方设计研究,用黑甜玉米油代替脂肪,用黑甜玉米酸奶强化营养,研制出一种新型保健冰淇淋。并通过一系列正交试验确定冰淇淋复合稳定剂的最佳配比和黑甜玉米酸奶冰淇淋的最佳配方,即瓜胶:耐酸CMC-Na:黄原胶:单甘酯为=2:1:1:2,黑甜玉米发酵乳40%,复合乳化稳定剂0.5%,全脂乳粉为12%,黑甜玉米油2%,白砂糖15%。按此工艺生产的冰淇淋不仅具有紧密的外观,而且具有光滑细腻的组织结构和醇厚持久的风味,同时提高了冰淇淋的营养价值。     

Use of acid whey protein concentrate as an ingredient in nonfat cup set-style yogurt

Acid whey resulting from the production of soft cheeses is a disposal problem for the dairy industry. Few uses have been found for acid whey because of its high ash content, low pH, and high organic acid content. The objective of this study was to explore the potential of recovery of whey protein from cottage cheese acid whey for use in yogurt. Cottage cheese acid whey and Cheddar cheese whey were produced from standard cottage cheese and Cheddar cheese-making procedures, respectively. The whey was separated and pasteurized by high temperature, short time pasteurization and stored at 4°C. Food-grade ammonium hydroxide was used to neutralize the acid whey to a pH of 6.4. The whey was heated to 50°C and concentrated using ultrafiltration and diafiltration with 11 polyethersulfone cartridge membrane filters (10,000-kDa cutoff) to 25% total solids and 80% protein. Skim milk was concentrated to 6% total protein. Nonfat, unflavored set-style yogurts (6.0 ± 0.1% protein, 15 ± 1.0% solids) were made from skim milk with added acid whey protein concentrate, skim milk with added sweet whey protein concentrate, or skim milk concentrate. Yogurt mixes were standardized to lactose and fat of 6.50% and 0.10%, respectively. Yogurt was fermented at 43°C to pH 4.6 and stored at 4°C. The experiment was replicated in triplicate. Titratable acidity, pH, whey separation, color, and gel strength were measured weekly in yogurts through 8 wk. Trained panel profiling was conducted on 0, 14, 28, and 56 d. Fat-free yogurts produced with added neutralized fresh liquid acid whey protein concentrate had flavor attributes similar those with added fresh liquid sweet whey protein but had lower gel strength attributes, which translated to differences in trained panel texture attributes and lower consumer liking scores for fat-free yogurt made with added acid whey protein ingredient. Difference in pH was the main contributor to texture differences, as higher pH in acid whey protein yogurts changed gel structure formation and water-holding capacity of the yogurt gel. In a second part of the study, the yogurt mix was reformulated to address texture differences. The reformulated yogurt mix at 2% milkfat and using a lower level of sweet and acid whey ingredient performed at parity with control yogurts in consumer sensory trials. Fresh liquid acid whey protein concentrates from cottage cheese manufacture can be used as a liquid protein ingredient source for manufacture of yogurt in the same factory.     

Growth and activity of some lactic streptococci cultivated on soymilk medium infected with bacteriophage

Pure cultures of S. lactis, S. cremoris, S. diacetilactis and S. thermophilus were cultivated on soymilk medium containing 3% lactose and skim milk medium which were infected or not infected with bacteriophage. The cultures were incubated for 24 h at the optimum temperature of each organism. The growth, lactic acid production and activity of each culture were periodically examined. The growth and the acidity development of the cultivated cultures on soymilk medium infected with bacteriophage increased gradually during the incubation period, whereas the cultures grown on skim milk infected with bacteriophage showed less growth and acid production. Moreover, the growth and the rate of lactic acid production of the cultures cultivated on soymilk medium were higher than those of the cultures grown on skim milk medium (control). Therefore, soymilk medium containing 3% lactose could be recommended as a protective medium against bacteriophage infection for lactic acid starter.     

Changes of soybean quality during storage as related to soymilk and tofu making

ABSTRACT:  Soybeans are stored and transported under various humidity and temperature conditions. Soymilk and tofu are two of the most important foods made from whole soybeans. The objective of this study was to investigate the influence of storage conditions on soybean quality as related to soymilk and tofu-making properties. Soybeans of 3 different genotypes (Proto, IA2032, and Vinton 81) were stored in varying conditions: temperature ranging from 4 to 50 °C, relative humidity from 55% to 80%, initial moisture content from 6% to14%, and storage time up to 15 mo depending upon storage conditions. The effects of different storage conditions on soybean color, solids and protein extractability, soymilk pH, tofu yield, tofu solids and protein contents, tofu color, and texture were investigated. While no significant changes occurred for the soybeans stored at 4 °C, the soybeans stored at high temperatures (30 to 50 °C) exhibited significant quality loss ( P < 0.05). The degradation of soybean lightness (Hunter L ), color difference (Δ E ), and solid extractability exhibited a linear relationship with time. Soak weight decreased at high temperature and relative humidity, but increased at mild storage conditions. Several combinations of storage conditions at temperatures exceeding 30 °C produced a drastic loss in tofu yield. Storage also affected the tofu making process by reducing optimum mixing time to produce the highest tofu yield. Varietal difference in soybean storability was observed. The results provided useful information for the soybean processing industry to store soybeans using the optimal storage conditions and to estimate soybean quality after storage.     

Influence of condensed sweet cream buttermilk on the manufacture, yield, and functionality of pizza cheese

Compositional changes in raw and pasteurized cream and unconcentrated sweet cream buttermilk (SCB) obtained from a local dairy were investigated over 1 yr. Total phospholipid (PL) composition in SCB ranged from 0.113 to 0.153%. Whey protein denaturation in pasteurized cream over 1 yr ranged from 18 to 59%. Pizza cheese was manufactured from milk standardized with condensed SCB (∼34.0% total solids, 9.0% casein, 17.8% lactose). Effects of using condensed SCB on composition, yield, PL recovery, and functional properties of pizza cheese were investigated. Cheesemilks were prepared by adding 0, 2, 4, and 6% (wt/wt) condensed SCB to part-skim milk, and cream was added to obtain cheesemilks with ∼11.2 to 12.7% total solids and casein:fat ratio of ∼1. Use of condensed SCB resulted in a significant increase in cheese moisture. Cheese-making procedures were modified to obtain similar cheese moisture contents. Fat and nitrogen recoveries in SCB cheeses were slightly lower and higher, respectively, than in control cheeses. Phospholipid recovery in cheeses was below 40%. Values of pH and 12% trichloro-acetic acid-soluble nitrogen were similar among all treatments. Cheeses made from milk standardized with SCB showed less melt and stretch than control cheese, especially at the 4 and 6% SCB levels. Addition of SCB significantly lowered free oil at wk 1 but there were no significant differences at wk 2 and 4. Use of SCB did not result in oxidized flavor in unmelted cheeses. At low levels (e.g., 2% SCB), addition of condensed SCB improved cheese yield without affecting compositional, rheological, and sensory properties of cheese.