Calcium Supplementation of Cottage Cheese

Cottage cheese (100 g) provides only 6% of the calcium Recommended Daily Allowance for adults. Samples of fresh cheese were supplemented with calcium salts (chloride, lactate, or phosphate monobasic) to double the calcium content of the cheese to approximately 145 mg/100 g, and the effects of the supplementation on taste and microbial stability were studied. Supplementations did not affect pH or microbial stability during 21 d of refrigerated storage. Sensory evaluation results of a 12-member taste panel showed higher flavor and preference scores for control than for all supplemented samples (P<.05) but no difference in odor, color, or texture. Overall, chloride appeared to be preferable for calcium content supplementation because only .26% (wt/wt) of the salt was required to obtain the desired calcium content level and the mineral was evenly distributed in the cheese.     

Evaluation of Alternative Methods to Increase Calcium Retention in Cottage Cheese Curd

The effect of several alternative methods including addition of rennet, addition of carrageenan and use of 2:1 (v/v) preconcentrated skim milk by ultrafiltration (UF) upon calcium retention, yield, composition and sensory properties of dry curd cottage cheese was investigated. Although each of the processing methods resulted in the manufacture of dry curd cottage cheese with different compositions and properties, none of them was satisfactory for increasing calcium retention. Added carrageenan bound additional whey proteins, added rennet interfered with curd syneresis and whey expulsion during cooking and use of UF preconcentrated skim milk resulted in an increase in yield, total solids and protein of the curd.     

瓜尔胶及改性瓜尔胶的性质及应用

本文介绍了瓜尔胶及改性瓜尔胶在造纸中的应用特性及最新研究成果。瓜尔胶及改性瓜尔胶系列助剂在提高纸页留着和滤水的同时能保持或提高纸页匀度，是一种前景广阔的环保助剂。阳离子瓜尔胶的新式捆绑系统是研究的热点。     

Synthesis and Characterization of Quaternary Ammonium Compounds of Guar Gum and Hydroxyethyl Guar Gum

The quaternary ammonium compounds of guar gum (QAGG) and hydroxylethyl guar gum ether (QAHEG) were prepared by the reaction of guar gum (GG) or hydroxyethyl guar gum ether (HEG) with amine condensates of epichlorohydrin using either aliphatic or heterocyclic tertiary amines. These quaternary salts were characterized by infra-red spectra, viscometry and thermogravimetry. The temperature characteristics like initial decomposition temperature (IDT), ten percent volatilization temperature (T₁₀), temperature of maximum rate of decomposition (T_max), integral procedural decomposition temperature (IPDT) and activation energy of QAGG and QAHEG salts are compared with those of GG and HEG.     

Nutritional Evaluation of Cheese Spread Powder

A study on the nutritional evaluation of processed cheddar cheese and cheese spread powder made from it, was undertaken. Levels of all constituents, except phosphorus and moisture contents, were significantly higher in cheese spray-dried powder as compared to processed cheese. Biological evaluation of the products showed that a Modified Protein Efficiency Ratio (PER_D), Net Protein Utilization (NPU), and Digestibility Coefficient (DC) and also regeneration of certain organs, in protein depleted albino rats fed diets based on processed cheese and spray-dired powder made from it, were identical.     

Nutritional Evaluation of Typical and Reformulated Italian Cheese

The aim of this work was the nutritional evaluation of reformulated dairy products (caciotta-type cheese) and manufactured either with a low-sodium chloride content (different salting time and/or composition of the brine) or low-fat content (different partially skimmed milks). These cheeses were intended for people on low-energy or low-sodium diets. A comparison was made between these new products and three typical Italian cheeses (Provolone, Taleggio and Pecorino Romano). The nutrient content of the products was determined. Amino acids by chromatographic methods, protein digestibility by an enzymatic method and lysine availability determined spectrophotometrically were shown not to be influenced by the salt reduction. The salt reduction also did not affect vitamin contents (riboflavin, retinols, carotenes and tocopherols) measured by HPLC methods, while the reduced fat contents (310 g kg^-1, 160 g kg^-1 and 87 g kg^-1) led to significant decreases in concentrations of fat-soluble vitamins (38% for tocopherols and 7% for total retinols) and a decrease in riboflavin (13%) due to the loss of riboflavin enzymes located on the fat globules (ie xanthine oxidase). Both the typical cheeses and the new formulations represent good sources of calcium and protein. Protein digestibility was affected by the ripening time; in fact, in Pecorino Romano, ripened for 6–9 months it reached 62% in 6 h, whereas in Taleggio and in all caciotta–cheeses it reached only 32–37%. The nutritional profiles of the reformulated caciotta cheese showed that these products could represent a good choice in low-energy and low-sodium diets, but an enrichment of fat-soluble vitamins is advisable in the low-fat products. © 1997 SCI.     

Effect of Guar Gum on the Physicochemical, Thermal, Rheological and Textural Properties of Green Edam Cheese

In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar gum modified cheeses were similar to those of the low-fat control. No significant differences were detected in the thermal properties (concerning the enthalpy and profile of water desorption) among all types of cheeses. The rheological behaviour of the 0.0025% modified cheese was very similar to the full-fat control. Overall, no trend was observed in the texture profile (hardness, cohesiveness, gumminess and elasticity) of the modified cheeses versus guar gum concentration, as well as in comparison with the control groups, suggesting that none of the studied polysaccharide concentrations simulated the textural functions of fat in Edam cheese.     

Nutritional Evaluation of Cereal–Cheese Whey Mixtures

The chemical composition, amino acid content, PER, and digestibility of dehydrated sweet cheese whey, wheat flour, wheat bran, and lime-treated corn flour (nixtamal, used for making tortillas), as well as of 21 cereal-cheese whey mixtures were determined. The cheese whey was composed of 12% protein and 74% lactose. Diets containing a total of 8% protein were formulated with the cereal-cheese whey mixtures. The 50:50 (% protein) cereal-whey mixtures had the highest adjusted modified PERs, representing an increase over the cereals alone of 324% for the corn flour, 215% for wheat flour, and 177% for wheat flour, and 177% for wheat bran. The 50:50 (% protein) wheat bran mixture had the largest adjusted modified PER at 2.33 ± 0.13 (mean ± SEM) and the 50:50 wheat flour mixture, the smallest at 1.48 ± 0.21. Although the apparent digestibility was reduced from 10–14% for the latter two 50:50 cereal-whey mixtures compared to the cereals alone, this was not reflected in the PER. It was concluded that the nutritive value of all the cereals tested significantly increased with the addition of 155 25% or more (by weight) of dehydrated cheese whey.     

Nutritional Evaluation of Accelerated Ripened Cheddar Processed Cheese

Accelerated ripened Cheddar cheese was prepared by blending two parts of shredded curd made from standardized cow's milk with one part of 5.2% NaCl solution and ripening at 30°C for 8 days. On a dry matter basis, protein and fat of accelerated ripened cheese were similar to that of conventionally ripened Cheddar cheese, while lactose and total ash were greater. Similar observation was made for processed cheese samples. No change in vitamin A or in riboflavin but a fourfold increase in folic acid was observed during accelerated ripening. Protein efficiency ratio, net protein utilization and digestibility coefficient by rat tests were slightly but significantly higher for conventionally ripened processed cheese. However, no difference in biological value was observed.     

Acceptability of Whey-Soy Drink Mix Prepared with Cottage Cheese Whey

Flavor score of commercially produced whey-soy drink mix containing 41% sweet whey solids was correlated with the lactic acid content of the dehydrated material (?.75). Experimental samples prepared with a 1:1 mixture of acid whey to sweet whey and neutralized acid whey showed lower initial flavor scores than a control prepared with only sweet whey. Both samples contained over 1% total lactate reported as lactic acid compared to .4% for the control. A sample prepared with a 1:5 mixture of acid to sweet whey contained .77% lactic acid. Flavor scores of this sample after 158 days storage at 37 C, although not significantly different from the control stored under similar conditions, showed a downward trend over time. Therefore, use of small amounts of acid whey in the formulation could lead to impaired storage stability as measured by flavor acceptability during prolonged storage under adverse conditions.     

Prediction and Characterization of Normal and Vat-Failed Cottage Cheese

An acidification-heat-coagulation test has been developed for predicting cottage cheese vat-failure potential of milk. Milk is fist acidified to pH 5.06 at 10°C and then heated at a slow rate (1°C increment per min). Poor quality acidified milk (> 10⁴ CFU/ml) forms small curds at 37°C and below. Good quality acidified milk (< 10⁴ CFU/ml) will form small curds at higher temperatures. By this procedure cottage cheese vat-failure potential of milk containing different levels of psychrotrophs can be predicted. Normal and vat-failed cottage cheese curds are characterized by % of grit in cottage cheese and amount of curd fines in whey.     

瓜尔豆胶和黄原胶对淀粉理化性质的影响

为改善淀粉的加工品质特性,以玉米淀粉和甘薯淀粉为研究对象,将瓜尔豆胶和黄原胶分别以不同比例(0.1%~0.5%)与淀粉进行复配,系统研究亲水胶体对淀粉理化特性等的影响。结果表明,添加亲水胶体后,随着胶体浓度的增加,复配体系的透光率逐渐下降,凝沉稳定性增大,膨胀度增大,淀粉胶体的硬度下降。RVA分析表明,加入亲水胶体使复配体系的糊化温度升高,峰值黏度、崩解值和终值黏度增加,而甘薯淀粉-黄原胶混合体系的峰值黏度显著降低。     

瓜尔胶的改性及在造纸工业中的应用

结合瓜尔胶的结构特点综述了其改性方法,并对瓜尔胶在造纸工业中的应用和最新研究成果进行了介绍,阐述了瓜尔胶是一种新型环保型造纸助剂,有着广阔的应用前景。     

纳米改性羟丙基瓜尔胶的制备及其应用研究

采用双氧水氧化降解制备了纳米改性羟丙基瓜尔胶,讨论了纳米改性羟丙基瓜尔胶对纸张表面施胶的效果.结果表明：双氧水用量为瓜尔胶质量的8.6％、反应温度为65℃、反应时间为4h,制得的纳米改性羟丙基瓜尔胶质量分数为1％的水溶液黏度从2390 mPa·s降到3.47mPa·s.纳米改性羟丙基瓜尔胶对滤嘴棒原纸的表面施胶较佳工艺条件为：表面施胶温度50～60℃、瓜尔胶水溶液质量分数为5％～8％.     

瓜尔胶及其衍生物的应用研究进展

瓜尔胶及其衍生物是新型的天然高分子化合物,应用前景广阔,综述了瓜尔胶及其衍生物的国内外应用研究进展,详细介绍了瓜尔胶及其衍生物在造纸工业、日用化学品工业、食品工业、石油钻探工业、医药工业等方面的应用,强调了其特殊性能的优势和应用潜力,阐明了我国研究开发瓜尔胶及其衍生物的意义     

食品增稠剂瓜儿豆胶性质及复配性的研究

本文对瓜尔豆胶的流变性,浓度、温度、pH值、电介质对粘度的影响,与黄原胶、卡拉胶复后粘度变化进行了初步研究。结果表明,低浓度瓜儿豆胶属非牛顿流体中假塑性流体,其粘度随浓度升高而上升,随温度升高而下降,几乎不受pH值影响,对NaCl和低浓度Ca~(2+),Al~(3+)有良好兼容性,与卡拉胶复配无增效作用,而与黄原胶复配增效显著,复配最佳比例为瓜儿豆胶:黄原胶=0.6:0.4     

Partial Deacidification and Demineralization of Cottage Cheese Whey by Nanofiltration

Nanofiltration (NF) membrane processing was investigated as a method for deacidifying and demineralizing cottage cheese whey (CCW) as function of pH 3.0 to 6.5 so that it could be used in ice cream and other frozen dairy desserts. Membrane flux values after 30 min processing ranged from 7.5 to 9.0 Lm^?2hr^?1. Total processing time to produce volume concentration ratio 3 (VCR3) retentate and diafiltration against 3 volumes of water to produce DNF3 retentate ranged from 87 to 93 min at pH 3–4.35 to 180 to 210 min at pH 5.5–6.5. DNF3 retentate contained 0.33% lactic acid, 0.65% ash, 11.55% lactose and 14.47% total solids. Membrane rejection of lactic acid ranged from 31% for VCR3 retentate to 67.2% for DNF3 retentate. Membrane rejection of minerals for VCR3 and DNF3 retentates was 30% and 71%, respectively.     

Starch Cooking with Limited Water as Affected by Zein and Guar Gum

DSC (Differential Scanning Calorimetry) peak temperature of starch was decreased by adding zein, but was increased by adding guar gum. Adding zein increased the initial rate of starch cooking, but adding guar gum decreased it. Kinetic studies were carried out at 115, 125, and 135°C. At25°C, zein absorbed less water than waxy corn starch, especially at water activities >0.6 where guar gum absorbed more water than starch. The strong binding of water by guar gum increased DSC-peak-temperature and decreased the initial rate of starch cooking. The relatively weak binding of water by zein decreased DSC peak temperature and increased the initial rate of starch cooking. Although water sorption data at cooking temperatures are difficult to measure, the kinetic data at these temperatures and DSC data could be used to supplement the sorption data.     

黄原胶魔芋胶复配改善夸克干酪品质的研究

为改善传统方法制作夸克干酪所带来的口感及风味上的不足,研究了黄原胶与魔芋胶复配在夸克干酪中的应用;采用四因素三水平正交设计研究了夸克干酪调配的最佳配方。结果表明:复合食品胶(黄原胶、魔芋胶复合的质量比为7∶3)与CMC配伍的稳定效果较好;当水添加量为30%、复合食品胶添加量为0.3%、CMC添加量为0.3%、白砂糖添加量为6%时,夸克干酪品质最佳。     

瓜尔胶的改性及其在造纸中的应用

概述了瓜尔胶的结构和性质,重点介绍了其化学改性方法及不同类型瓜尔胶衍生物在造纸工业中的应用.