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).     

Manufacture of nonfat yogurt from a high milk protein powder.

Nonfat yogurts were manufactured from skim milk fortified with a new high milk protein powder. The powder, containing approximately 84% milk protein, was added to skim milk to obtain 5.2 to 11.3% total protein, 11.1 to 15% total solids, and 1.6 to 7.9% lactose in the yogurt mix. Mixes were homogenized, pasteurized at 90 degrees C for 10 min, and fermented with a yogurt culture at 42 degrees C to pH 4.6. Controls were made from the same skim milk fortified with NDM to approximately 14% total solids. Yogurts made with the protein powder and containing 5.6% protein were similar in firmness to the control and had good flavor when fresh and after 2 wk of storage. Yogurts with more than 5.6% protein were too firm and had an astringent flavor. Acetaldehyde content of all yogurts was comparable with that of the control, and fat content ranged from .18 to .33%. As the protein content of yogurts increased, the porosity of yogurts, as seen by scanning electron microscopy, decreased. Good quality nonfat yogurts can be produced by supplementing skim milk with a high milk protein powder up to 5.6% protein. The added protein assists in providing a firm body and minimal whey separation without the use of stabilizers.     

不同品种原料乳理化特性分析

主要分析荷斯坦牛、牦牛、娟珊牛、摩拉水牛、尼里-拉菲水牛、Ⅰ代杂交水牛、高代杂交水牛等7个品种的原料乳的常规营养成分,并对原料乳中蛋白质和氨基酸组成及牛乳缓冲能力进行测定。结果显示：摩拉水牛、尼里-拉菲水牛、Ⅰ代杂交水牛和高代杂交水牛的乳脂肪含量分别为6.86%、7.99%、8.34%、8.69%,蛋白质含量分别为5.75%、5.14%、5.78%、5.58%,干物质含量分别为17.07%、18.79%、19.73%、19.88%,显著高于其他3种牛乳;牦牛和娟珊牛乳中乳糖含量分别为5.09%、5.17%,显著高于其他5种牛乳。SDS-PAGE显示：水牛乳中除含有牛乳血清蛋白(BSA)、α-酪蛋白(α-CN)、β-酪蛋白(β-CN)、κ-酪蛋白(κ-CN)、β-乳球蛋白(β-Lg)和α-乳白蛋白(α-La)主要蛋白外,还含有一些未定性蛋白;且水牛乳具有最好的缓冲性能,其次是牦牛乳和娟珊牛乳,荷斯坦牛乳缓冲性能最差。     

高效液相色谱法测定乳与乳制品中的三聚氰胺

目的建立乳与乳制品中三聚氰胺的测定方法。方法样品用0.1 mol/L的盐酸提取,再用60 g/L的磺基水杨酸沉淀蛋白。缓冲液为10 mmol/L柠檬酸与10 mmol/L辛烷磺酸钠混合溶液,以缓冲液 乙腈(85 15,体积比)为流动相,使用Kromasil KR100-5C8柱,配备有二极管阵列检测器的高效液相色谱仪在200~400 nm范围内对待测组分进行分离和测定。结果样品中三聚氰胺的添加回收率在80%~105%之间,相对标准偏差(RSD,n=6)小于5.24%,方法的定量限为1.0 mg/kg。结论该方法快速、准确,操作简便,能够满足乳与乳制品中三聚氰胺的分析要求。     

A Simple and Fast Detection Method for Bovine Milk Residues in Foods: A 2‐Site Monoclonal Antibody Immunochromatography Assay

The ingredient declaration on food labels assumes paramount importance in the protection of food‐allergic consumers. China has not implemented Food allergen labeling. A gold immunochromatography assay (GICA) was developed using 2 monoclonal antibodies (mAb) against the milk allergen β‐lactoglobulin in this study. The GICA was specific for pure milk samples with a sensitivity of 0.2 ng/mL. Milk protein traces extracted from 110 food products were detected by this method. The labels of 106 were confirmed by our GICA method: 57 food samples originally labeled as containing milk were positive for β‐lactoglobulin and 49 food samples labeled as not containing milk were negative for β‐lactoglobulin. However, 3 food samples falsely labeled as containing milk were found to contain no β‐lactoglobulin whereas 1 food sample labeled as not containing milk actually contained β‐lactoglobulin. First, these negatives could be because of the addition of a casein fraction. Second, some countries demand that food manufacturers label all ingredients derived from milk as “containing milk” even though the ingredients contain no detectable milk protein by any method. Our GICA method could thus provide a fast and simple method for semiquantitatation of β‐lactoglobulin in foods. Practical Application: The present method provides a fast, simple, semiquantitative method for the determination of milk allergens in foods.     

Improvement of low fat mozzarella cheese properties using denatured whey protein

Mozzarella cheese was made from buffalo milk (6% fat) or from partially skimmed buffalo milk (2 and 4% fat) with 0.5 and 1% denatured whey protein. Adding whey protein to buffalo milk decreased rennet coagulation time and curd tension whereas increased curd synaeresis. Addition of whey protein to cheese milk increased the acidity, total solids, ash, salt, salt in moisture, also some nitrogen fractions. The meltability and oiling‐off values increased but the calcium values of mozzarella cheese decreased. The sensory properties of low fat mozzarella cheese were improved by addition of whey protein to the cheese milk.     

Simultaneous Determination of 10 Photoinitiators in Milk by Solid‐Phase Microextraction Coupled with Gas Chromatography/Mass Spectrometry

Photoinitiators (PIs) are widely used in food packaging materials, can migrate easily from packaging materials to food, and cause food contamination. It is essential to establish a method of determining PIs residues in food. A new method for simultaneously determining 10 kinds of PIs in milk has been established by using solid‐phase microextraction (SPME) combined with a simple method of protein precipitation as the pretreatment approach and gas chromatography/mass spectrometry as the detecting technique. The limits of detection for 10 PIs in different milks were between 0.05 and 1.4 μg/L (skimmed milk), between 0.07 and 2.2 μg/L (semi‐skimmed milk), between 0.11 and 4.4 μg/L (whole milk), respectively. The recoveries were from 71.5% to 133.5%, and the relative standard deviations were less than 15%. Twelve kinds of packed milk with different brands and fat contents were determined using this method.     

不同哺乳动物乳中主要营养成分比较的研究进展

通过对牛乳、水牛乳、绵羊乳、山羊乳、骆驼乳和人乳中的蛋白质、脂肪、乳糖、矿物质和维生素等主要营养成分进行比较,发现山羊乳总体营养成分接近于人乳,对婴幼儿有极高的营养价值;绵羊乳和水牛乳中干物质含量较高,有利于开发成乳粉类产品;骆驼乳中含有丰富的不饱和脂肪酸,应在功能食品开发方面加以重视。      

Determinants of specific food consumption in the Canary Islands (Spain)

The consumption of specific functional foods (FF) and some determinants of FF item selection were assessed using a questionnaire administered to 1112 individuals in the Canary Islands (Spain). Food items considered were Milk products: easily digestible milk (or milk low in lactose), milk enriched with vitamins and/or minerals, skimmed milk with soluble fiber, milk with royal jelly, milk with modified fatty acids (omega 3), milk products low in fat, pro-biotic foods (yoghurt and fermented milk) and yoghurt with phytosterols; Cereals: fortified breakfast cereals, wholemeal cereals and energy bars; Drinks: juices and enriched drinks, stimulating drinks and isotonic drinks; DHA-enriched, low cholesterol eggs; Meat products: low salt sausages and cooked low fat ham; Fats: enriched margarine, margarine rich in phytosterols and sunflower oil rich in oleic acid; Condiments: iodated salt. These food items were organized into 7 FF groups (milk products, cereals, fortified drinks, DHA eggs, meat product, fats, condiments). The results indicated that the highest prevalence was fortified drinks (63.6%; 95% CI: 60.7-66.5). Overall FF consumption prevalence was 80.1% (95% CI: 77-83): single FF item consumption being rare. There were significant inter-group relationships, and some group intakes (milk products, cereals and drinks) were related to age but with no overall relationship between consumption and age. The education level was significantly related to the consumption of cereals, drinks, meat products and condiments (χ2 test p = 0.04). Some specific FF item consumption segregated with environment (rural or urban) but with no overall significant relationship between the FF group and environment or gender.     

中国母乳组学队列研究与产业化应用

母乳为婴儿提供个性化、全面、均衡的营养成分以及免疫保护,是0～6月婴儿的最佳营养来源,是婴儿食物的金标准。母乳组学队列研究是全面解析中国母乳组成特征、建立中国婴儿食品规范与标准、制定婴儿营养指南、创制婴儿食品的必要前提。本文介绍了国家母婴乳品健康工程技术研究中心基于中国母婴营养健康出生队列研究（China maternal and infant nutrition health birth cohort study,MINC）的母乳脂质组学、糖组学、蛋白质组学和微生物组等组学检测技术、组成特征、与牛乳的差异及其在婴儿食品中的产业化应用等方面的研究进展,以期为母乳组学队列研究、模拟与产业化应用提供科技支撑与示范。     

Development of a Food Mixture for Infants and Young Children in Brazil

SUMMARY-The development of food mixtures containing vegetable protein concentrates, minerals, and vitamins represents an important approach to the problem of protein-calorie malnutrition of preschool children in many parts of the world. In Brazil, soy flour is the most readily available good-quality protein for this purpose. Protein efficiency-ratio studies in rats demonstrated that soy flour with a PER value of 1.99 was available in large quantities. Accordingly, a formula containing 19.50% soy flour, 4.50% nonfat milk powder, 32.28% corn starch, 39.00% sucrose, and 4.72% vitamins and minerals was thoroughly tested as an infant food. The PER value of the protein in rats was 2.31. Amino acid assay demonstrated that the protein compared favorably with the essential amino acid pattern of the FAO/WHO reference protein (FAO/WHO, 196.5) except for methionine-cystine, The formula was well accepted and tolerated by children and adults. Average nitrogen absorption and retention of the formula as the sole food of malnourished children were 72.68 and 23.82%; values for milk protein were 80.17 and 30.13%. Average nitrogen absorption and retention were 63.4 and 22.0% when the formula provided one-half (15 g) of the daily protein for normal children consuming a typical diet of the region, comparing favorably with values of 69.3 and 21.3% for milk protein.     

The Physico-chemical, Sensory, and Textural Properties of Misti Dahi Prepared from Reduced Fat Buffalo Milk

High-fat and sugar content may pose a hurdle for the successful marketing of misti dahi because of growing awareness of health impact of these main ingredients among consumers. There is no literature available on the impact of milk fat reduction on the quality of misti dahi. Hence, the effect of reduction of milk fat, by keeping the total milk solids constant, was studied on the physico-chemical, sensory, and textural properties of buffalo misti dahi. Fresh raw buffalo milk was divided into three batches and was standardized to three different levels of milk fat viz., 1.5%, 3.0%, and 5.0% using fresh raw skimmed buffalo milk, and the total milk solids (TMS) content was adjusted to 18.0% using skimmed milk powder. The batch containing 5.0% fat was considered as control. Acidity, whey separation, viscosity, water activity (a _w), lightness (L*), redness (a*), yellowness (b*), firmness, stickiness, work of shear and work of adhesion were determined. Sensory evaluation was carried out using a nine-point hedonic scale method. Significant differences (p < 0.05) were observed in the flavour, body and texture, and overall acceptability of misti dahi, with 3.0% fat being better than 1.5% fat product. Acidity increased with the decrease in fat. Fat reduction did not cause any significant changes in the L*, a* and b* values and water activity of misti dahi. The firmness values of misti dahi with 1.5% fat were higher than that of 3.0% fat, but the difference was not significant. The stickiness value of misti dahi with 1.5% fat was more than the control, but the difference was not significant. Hence, on the basis of above results it is concluded that highly acceptable reduced fat misti dahi can be produced with 3.0% fat and 15.0% milk solids-not-fat (MSNF).     

The Microstructure and Physicochemical Properties of Probiotic Buffalo Yoghurt During Fermentation and Storage: a Comparison with Bovine Yoghurt

The physicochemical and rheological properties of yoghurt made from unstandardised unhomogenised buffalo milk were investigated during fermentation and 28 days of storage and compared to the properties of yoghurt made from homogenised fortified bovine milk. A number of differences observed in the gel network can be linked to differences in milk composition. The microstructure of buffalo yoghurt, as assessed by confocal laser scanning microscopy (CLSM) and cryo scanning electron microscopy (cryo-SEM), was interrupted by large fat globules and featured more serum pores. These fat globules have a lower surface area and bind less protein than the homogenised fat globules in bovine milk. These microstructural differences likely lead to the higher syneresis observed for buffalo yoghurt with an increase from 17.4 % (w/w) to 19.7 % (w/w) in the weight of whey generated at days 1 and 28 of the storage. The higher concentration of total calcium in buffalo milk resulted in the release of more ionic calcium during fermentation. Gelation was also slower but the strength of the two gels was similar due to similar protein and total solids concentrations. Buffalo yoghurt was more viscous, less able to recover from deformation and less Newtonian than bovine yoghurt with a thixotropy of 3,035 Pa.s^?1 measured for buffalo yoghurt at the end of the storage, at least four times higher than the thixotropy of bovine yoghurt. While the titratable acidity, lactose consumption and changes in organic acid concentrations were similar, differences were recorded in the viability of probiotic bacteria with a lower viability of Lactobacillus acidophilus of 5.17 log (CFU/g) recorded for buffalo yoghurt at day 28 of the storage. Our results show that factors other than the total solids content and protein concentration of milk affect the structural properties of yoghurt. They also illustrate the physicochemical reasons why buffalo and bovine yoghurt are reported to have different sensory properties and provide insight into how compositional changes can be used to alter the microstructure and properties of dairy products.     

人乳营养成分及其生理功能

人乳是婴儿最天然的理想食品,是婴儿早期的主要营养物质来源,含有丰富的营养物质及生物活性成分,包括蛋白质、脂肪、碳水化合物、矿物质、维生素及分泌型免疫球蛋白、牛磺酸等。人乳中各成分含量适中,比例适宜,有利于婴儿早期生长发育及随后的健康成长,并具有促进婴儿肠道、神经、免疫等系统发育的作用。文章概述了人乳中主要的营养成分及其生理功能,与牛乳做对比,为婴儿的喂养管理提供基础,进而为牛乳基婴幼儿配方奶粉的设计提供理论指导,对生产母乳化的婴幼儿配方奶粉具有重要意义。     

Response of Holstein and Brown Swiss cows fed alfalfa hay-based diets to supplemental methionine at two stages of lactation

In this study, we evaluated the effects of dietary supplementation at two stages of lactation with various levels of Mepron85 (M85) and M85 plus DL-methionine (DL-Met) on milk production and composition of Holstein and Brown Swiss cows fed an alfalfa-hay and corn grain-based diet. In experiment 1, control diets were formulated to supplement, in early lactation [days in milk (DIM) = 73.2], concentrations of metabolizable methionine at 104% of the estimated requirements based on the Cornell Net Carbohydrate and Protein System. Treatment groups were fed the control diet plus 10, 20, or 30 g/d of M85 at 116, 128, or 139% of the estimated requirements for metabolizable methionine. The supplementation with 10 g/d in Brown Swiss and 30 g/d of M85 in Holstein cows increased milk yields and fat percentage, but had no effects on protein percentage. These data suggested that the estimated postruminal supply of metabolizable methionine in the control ration was limiting for maximum milk fat synthesis. Conversely, in experiment 2, the cosupplementation with M85 (15 g/d) plus DL-Met (15 g/d) to cows in midlactation (DIM = 140.5) did not influence fat percentage, but increased protein yield and percentage (+0.1%) in both Holstein and Brown Swiss, and lactose percentage (+0.18%) in Holstein cows. The supplementation with 15 g/d of M85 reduced milk and protein yields, whereas 15 g/d of DL-Met reduced protein percentage in four of the five experimental weeks for Holstein cows. We conclude that supplementation with M85, alone or in combination with DL-Met, may be used to influence milk composition, but these effects are influenced by dosage and type of supplemental methionine, breed, and stage of lactation.     

Isolation and Characterization of Buffalo Milk Lysozyme

Lysozyme is a commercially valuable enzyme, and is applied in many fields, concerning products such as foods, drugs, and the like. In this work, lysozyme was isolated and purified from buffalo milk using sephadex G-50 and cation exchanger carboxymethyl cellulose. Lysozyme active fractions from buffalo milk were assayed against Gram positive substrate Micrococcus luteus at 450 nm and a decline in absorbance of 0.001 per min was observed. The optimum activity of lysozyme (158.3 ± 1.7 units/mL) was at 7.5 pH and 37°C temperature. Lysozyme activity at pasteurization temperatures 62.5°C, 30 min and 75°C, 15 s were (156.08 ± 1.03 and 156 ± 2 units/mL) not affected significantly; however, 47% activity of lysozyme was reduced at 100°C for 5 min. Antibacterial susceptibility testing of lysozyme (chicken egg white lysozyme and buffalo milk lysozyme) was performed on Micrococcus luteus (ATCC 4698) and Escherichia coli (ATCC 25235). Both lysozymes showed no inhibition effect against Escherichia coli.     

Modification of Physicochemical Characteristics of Goat Milk Fat by Feeding Protected High Oleic Sunflower Oil Supplements

ABSTRACT: Protein-oil supplements containing high oleic sunflower oil (HOSO) and different proteins were prepared and fed to lactating goats. Milk fat from goats on basal diet had 12.5% oleic acid (C18:1n9), but C18:1n9 increased ( P < 0.05) to 19.0% on the keratin protein-oil supplement diet, 19.2% on the casein protein-oil supplement diet, and 25.2% on dry casein (DC) protein-oil supplements diet. Feeding protein-oil supplements increased ( P < 0.05) levels of triacylglycerols with 46 and 50 carbons in milk fat and decreased ( P < 0.05) solid content in milk fat at 10°C from 34.8% to 23.0% for DC, to 26.5% for casein, and to 29.6% for keratin. The DC protein-oil supplement diet might produce spreadable butter out of the refrigerator.     

乳脂肪球膜的特性、开发及在模拟母乳脂肪球结构中的应用

乳脂肪球膜（milk fat globule membrane,MFGM）是包裹在天然乳脂肪球外部的3 层膜状结构,然而牛乳基和大豆基婴儿配方奶粉缺少MFGM,脂肪球结构与母乳存在较大差异,因此添加外源MFGM以及制备与母乳脂肪球结构接近的婴儿配方奶粉成为了近期的研究焦点。本文综述了MFGM的相关特性和生产开发途径,以及牛乳MFGM在仿母乳脂肪球结构乳液和婴儿配方奶粉中的应用。体外模拟婴儿胃肠道消化实验以及啮齿动物体内实验结果表明,仿母乳脂肪球结构乳液和婴儿配方奶粉能够促进婴儿脂肪消化并且改善脂质代谢过程。     

Vitamin A Stability in Ultra-High Temperature Processed Milk

Stability of vitamin A in partly skimmed (2% fat) fortified and unfortified ultra-high temperature processed milk was examined over 15 wk. Milk samples (stored at 23 ± 2°C) were analyzed weekly for retinyl palmitate and dissolved oxygen. Significant losses of 71 and 73% were observed in replicate samples of fortified milk containing initial vitamin A of 119 and 91 µg retinyl palmitate/100 ml, respectively. An unfortified milk sample with initial vitamin A of 86 µg retinyl palmitate/100 ml showed a loss of 62% whereas the replicate sample with initial vitamin A of 28 µg retinyl palmitate/100 ml remained unchanged during storage. Dissolved oxygen in all four milk samples underwent significant changes. During the first 7 wk, oxygen declined or remained constant. After 7 wk, oxygen in all samples steadily increased.     

Effect of Milk Fat on the Stability of Vitamin A in Ultra-High Temperature Milk

The stability of vitamin A in ultra-high temperature milks with .15, 2.92, 6.16, and 9.7% fat during storage at 26°C was studied over 3 wk. Milks were fortified with synthetic retinyl palmitate to a final concentration of approximately 120 μg retinol equivalent/I 00 ml milk. The four milk samples were ultra-high temperature processed and packaged in 100 ml sterile milk dilution bottles and stored in the dark at 26°C for 3 wk. Vitamin A concentrations decreased rapidly during the first 2 wk of storage then stabilized. Degradation rates during the first 2 wk were linear and varied inversely with the fat content in the milk (the more fat, the slower the rate of degradation). Final vitamin A concentrations at the end of 3 wk of storage were higher in milk with high fat and closely corresponded to the native vitamin A concentrations present in milk prior to fortification. The results indicate a possible protective effect due to fat or a difference in stability between native and synthetic vitamin A.