唾液酸在婴幼儿配方奶粉中的应用进展

母乳中含有丰富的唾液酸成分,大多数唾液酸是以与低聚糖结合的形式存在。目前,已有报道称唾液酸可以促进婴儿的大脑和神经系统的发育,但唾液酸的代谢机制和生物功能并不十分清晰。更重要的问题是,唾液酸作为一个在母乳中的有效营养成分,将其添加到婴幼儿配方奶粉中会有哪些优势体现尚不明确。课题对唾液酸的基本特性、生物活性、检测方法以及应用现状做了全面的概述,并对唾液酸未来应用于婴幼儿配方奶粉的可行性提供了可靠依据。     

废弃鸡蛋壳的化学组成及其中唾液酸的生物学功能

主要阐述了废弃鸡蛋壳的化学组成以及其中生物活性物质唾液酸的生物学功能问题.废弃蛋壳包括蛋壳、蛋壳膜和残留蛋清,含有唾液酸、糖醛酸以及氨基酸等成分.其中唾液酸是一类分布在复合糖类糖链末端的九碳糖,在各种生命活动中起着重要的作用,如体内润滑、维持正常神经活动、益智、抗菌、抗病毒、抗肿瘤等,旨在为废弃蛋壳中唾液酸的开发利用以及今后相应的科研工作提供理论依据.     

二十二碳六烯酸单细胞油(DHASCO)--婴幼儿及孕产妇的DHA营养补充剂

DHA是大脑中最丰富的长链多不饱和脂肪酸之一,也是视网膜光受体中最丰富的多不饱和脂肪酸.然而人体,特别是婴幼儿自身合成DHA的能力有限,缺乏DHA会影响大脑和视力的发育及其功能,故从饮食中摄取足够的DHA十分重要.鱼油是目前DHA的主要来源,但鱼油中与DHA同时存在的EPA会影响婴儿的生长发育,因此鱼油不适合添加进婴幼儿配方食品中.利用现代生物技术生产的二十二碳六烯酸单细胞油含有40%左右的高纯度DHA,几乎不含EPA,产品已能工业化生产,各种理化指标稳定,纯度和安全性优于鱼油,目前已开始应用于婴幼儿奶粉和作为功能性食品原料使用.评述了二十二碳六烯酸单细胞油的原料来源、制作过程、理化性状、吸收代谢、安全性以及在婴幼儿、孕产妇的临床功能研究等方面的研究进展,并对二十二碳六烯酸单细胞油在保健食品中的应用情况作了简单的介绍.     

由鸡蛋黄粉制备含唾液酸的水解液

研究了从鸡蛋黄粉制备含有唾液酸的水解浓缩液(可从中进一步精制出唾液酸成品)的方法,包括蛋黄粉的脱脂方法,脱脂蛋黄粉水解条件的优化,水解清液的超滤和纳滤浓缩、除盐。最终制得的水解液中含唾液酸1200μg/mL,相当于从每克干重的脱脂蛋黄粉中游离出了1.67mg的唾液酸。     

酪蛋白糖巨肽的生理功能及发展前景

酪蛋白糖巨肽（casein Glycomacmpepride，简称CGMP）是一种含有唾液酸的糖肽，用凝乳酶或酸性蛋白酶水解牛乳酪蛋白（主要是K-酪蛋白），乳清中含有CGMP。简述CGMP的化学结构、制备、检测方法、生物活性、研究现状及应用前景。     

唾液酸的生理功能、应用及其生产方法

唾液酸广泛的分布于多种生物组织中,通常位于非还原性寡聚糖的末端。在各种生命活动调节过程中起着重要的作用。唾液酸在食品和医药等领域的应用潜力,决定了需要对其进行大规模生产的必要性。本文对唾液酸的生理功能、应用和生产方法进行了综述,并对其未来发展方向进行了展望。     

国内外婴幼儿食品中蛋白质质量评价方法的对比研究

婴幼儿食品中蛋白质的质量直接影响着婴幼儿的健康成长.本文论述了目前国内外婴幼儿食品中蛋白质质量的评价方法,主要对数值评价、消化率评价、生物学评价和氨基酸评价4类方法进行对比分析,结果表明:用蛋白质消化率校正的氨基酸记分法(PDCAAS)是各种方法中相对较完善的方法.本研究结果对促进我国婴幼儿食品品质的鉴定、新的食品资源的研究和开发以及婴幼儿合理膳食指导具有重要的意义.     

喷雾干燥在功能性食品微胶囊化中的应用

功能性食品通常含有对机体组织有益的活性成分,对保障机体的健康起到非常重要的作用。但是,功能性食品中的活性成分大多都不稳定,易被降解,因此需要对其进行包埋。喷雾干燥是用于功能性食品微胶囊化的常用方法。目前,喷雾干燥已广泛用于香料、脂类和类胡萝卜素等活性成分的包埋。从喷雾干燥的基本过程、影响因素、喷雾干燥在制备功能性食品微胶囊中的应用以及未来发展趋势等方面展开综述,为喷雾干燥在功能性食品微胶囊化中的进一步应用提供理论基础和研究方向。     

原子吸收光谱法在婴幼儿食品检测中的应用

对应用原子吸收光谱法分析婴幼儿食品中某些金属元素的应用范围、样品的制备方法进行了较详细的阐述,并列举了一些金属元素测定方法的实例。     

唾液酸生物活性及其应用的研究进展

对唾液酸的来源、检测手段、生物活性及其在食品医药领域应用等方面的研究进行了综述,并对其未来的发展方向进行了展望。     

Determination of sialic acids in infant formula by chromatographic methods: a comparison of high-performance anion-exchange chromatography with pulsed amperometric detection and ultra-high-performance liquid chromatography methods

Sialic acid determination in an infant formula presents many challenges, including efficient sialic acid release from glycoconjugates, effective sample preparation, and rugged chromatography. This work compares 2 chromatographic assays developed for determination of sialic acids in infant formula. Prior to chromatography, both assays release sialic acids by acid hydrolysis and treat the hydrolysate with a subsequent anion-exchange sample preparation. Both high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and fluorescence ultra-high-performance liquid chromatography (UHPLC) sample analysis methods were evaluated to compare assay performance and convenience. Calibration ranges were chosen to encompass the expected amounts of 2 sialic acids in infant formula: N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc). Response was linear by either method with coefficients of determination of 1.00 by HPAEC-PAD between 5.0 and 100pmol of Neu5Ac and between 0.34 and 6.8 pmol of Neu5Gc and >0.99 by UHPLC between 5.0 and 260 pmol of Neu5Ac and between 0.20 and 9.8 pmol of Neu5Gc. Both methods had sufficient sensitivity to determine these sialic acids in infant formula. Three infant formulas were analyzed to evaluate accuracy and precision of the assays. The HPAEC-PAD assay was found to be faster overall and the UHPLC assay was more sensitive. Reaction efficiency, and therefore sensitivity, was dependent on the sample matrix. This work illustrates sample-specific complexity that must be considered in choosing an assay.     

Sialyloligosaccharides in human and bovine milk and in infant formulas: variations with the progression of lactation

Several lines of research support a role for human milk oligosaccharides in the defense of breast-fed infants against pathogens. Some ofthese oligosaccharides contain at least one moiety of sialic acid and are, thus, termed sialyloligosaccharides. These constitute a significant component (>1 g/L) of human milk. It is well established that milk composition varies among species, and previous reports have indicated that one ofthe differences between human and bovine milk is precisely their contents of sialyloligosaccharides. Because most infant formulas are manufactured with bovine milk components, it follows that formula-fed and breast-fed infants ingest dissimilar quantities of these carbohydrate structures. To ascertain these differences and their impact along lactation, the contents of oligosaccharide-bound sialic acids and major sialyloligosaccharides in samples of human and bovine milk (obtained at different lactation stages) were determined. In addition, infant formulas were assayed for their sialyloligosaccharide contents. Seven sialyloligosaccharides were identified in human milk; namely, 3'-sialyl-3-fucosyllactose and sialyllacto-N-tetraoses (a and b+c), the predominant structures at all lactation stages. Five sialyloligosaccharides were identified in bovine milk, of which 6'-sialyllactosamine and 3'-sialyllactose were the most abundant. In addition, sialyloligosaccharides in human and bovine milk decreased along lactation, and infant formulas did not contain significant amounts of sialyloligosaccharides. The results point to the general conclusion that regarding both qualitative and quantitative aspects, milk from humans and cows and infant formulas have different oligosaccharide contents. In this sense, bottle-fed infants are subject to reduced sialyloligosaccharide intake as compared to breast-fed infants.     

Comparison of spectrophotometric and HPLC methods for determining sialic acid in infant formulas

Two methods for determining sialic acid in infant formulas – spectrophotometry and HPLC with fluorescence detection – have been optimised and validated, the first one allows to determine total sialic acid while the second allows to differentiate the two main forms of sialic acid (N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc)). A common sample preparation procedure (hydrolysis and purification) for both methods has been proposed. The linearity (from 6 to 150 μg of total sialic acid in the assay for spectrophotometry, and from 12.5 to 250 ng and 1 to 5 ng of Neu5Ac and Neu5Gc, respectively, for HPLC) is adequate. The detection and quantification limits (0.29 and 0.97 mg of total sialic acid/L of reconstituted sample, respectively, for spectrophotometry, and 0.03 and 0.08 mg Neu5Ac/L; 0.003 and 0.009 mg Neu5Gc/L of reconstituted sample, respectively, for HPLC) are low enough for the determination of sialic acid in infant formulas. The precision of both methods, expressed as relative standard deviation, is less than 6%, and the accuracy evaluated by recovery assays show 104% recovery for spectrophotometry; 95% for Neu5Ac and 109% for Neu5Gc for HPLC. Samples analysed show no significant differences (α < 0.05) attributable to the method used; consequently, both of them could be applied after common sample preparation, the choice of technique depending on the facilities available in the laboratory.     

高效液相色谱法测定母乳中唾液酸含量

建立荧光高效液相色谱(fluorescence detector-high performance liquid chromatography,HPLC-FLD)测定母乳中唾液酸N-乙酰神经氨酸(N-acetylneuraminic acid,Neu5Ac)和N-羟乙酰神经氨酸(N-glycolyl neuraminic acid,Neu5Gc)含量的分析方法。利用酸水解法释放出母乳中的唾液酸,以4,5-亚甲二氧基-1,2-邻苯二胺盐(4,5-methylenedioxy-1,2-phenylenediamine dihydrochloride,DMB)为衍生化试剂,50℃避光衍生150min,采用荧光高效液相色谱仪检测。色谱条件：LiChrosorb RP-18柱(250mm×4mm,5μm),流动相为甲醇-乙腈-超纯水(7:8:85),流速0.9mL/min,进样体积10μL,柱温30℃,荧光检测器激发波长373nm,发射波长448nm。结果表明：唾液酸在50～400μmol/L范围内与唾液酸峰面积的线性关系良好,平均回收率为94.0%,精密度的相对标准偏差(relative standard deviation,RSD)为0.4%,稳定性RSD为1.0%,重复性RSD为0.8%,Neu5Ac的最低检出限为0.02μmol/L,Neu5Gc的最低检出限位0.03μmol/L。该方法简单、重复性好、灵敏度高,可广泛用于奶粉、牛奶及母乳中唾液酸含量测定。     

Distribution of bovine milk sialoglycoconjugates during lactation

The sialoglycoconjugate content of human milk has been extensively studied. However, little attention has been paid to the changes occurring in these compounds in bovine milk during lactation. Since sialoglycoconjugates are very abundant in milk from the early stages of lactation, they have been suggested to be important for the nutrition of the newborn during the first months of life. The distribution of sialoglycoconjugates (expressed as glycoconjugate-bound sialic acid) from four different stages of lactation (colostrum, transitional, mature, and late-lactation milks) was investigated in four Spanish-Brown cows. All the fractions studied (total sialic acids, glycoproteins, oligosaccharides, casein, and gangliosides) showed a similar trend. We found the highest values in the colostrum, these decreasing in transitional and mature milks and increasing again in late-lactation milk. We also found a selective change in the relative contents of glycoprotein- and oligosaccharide-bound sialic acids. In mature milk, the latter increased up to 80% (59% in colostrum) and the former decreased to 3.9% (35.3% in colostrum). It would appear that the decrease in oligosaccharide-bound sialic acid is compensated by the increase in glycoprotein-bound sialic acid. From these results, it is deduced that newborn infants or calves fed with infant formulas or milk replacers, respectively, should be supplemented with sialoglycoconjugates to approximate the composition of human and cow milk as far as is practicable.     

Determining Neu5Ac in infant formula with ultra‐performance liquid chromatography–tandem mass spectrometry

The aim of this work was to measure N‐acetylneuraminic acid (Neu5Ac) in milk‐based infant formulas. The analysis was performed by ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS). The total Neu5Ac were released using trichloroacetic acid and hydrochloric acid and purified using a HLB column. The linearity from 0.05 to 5.0 μg/mg Neu5Ac was adequate. Sialic acid recoveries ranged from 91.8% to 112.4%. The detection and quantification limits (limit of detection, 0.01 μg Neu5Ac/mg; limit of quantitation, 1.08 μg Neu5Ac/mg) were low enough to determine the sialic acid in infant formulas. The validated method is highly reproducible and sensitive, and it is easy to perform.     

膳食纤维与益生元在婴幼儿奶粉中的应用研究进展

膳食纤维作为一种新兴的营养配料,在保健品、食品中获得了良好的应用,但是在婴幼儿配方食品中一直没有突破。2012年1月12日,卫生部批准水溶性膳食纤维-聚葡萄糖作为营养强化剂应用于婴幼儿配方食品,对婴幼儿食品市场是一个福音。本文着重从发达国家对聚葡萄糖在婴幼儿食品中开展的相关试验入手,进一步探讨聚葡萄糖在婴幼儿食品中应用的可行性,为推动婴幼儿食品健康做出一些前瞻性的研究。     

Documentation of fatty acid profiles in lamb meat and lamb-based infant foods

Lamb meat, when used in the weaning diet of children, is presumed to have a lower allergenicity than other forms of red meat. In children with atopic dermatitis and multiple food hypersensitivities, consumption of lamb meat has also resulted in significant clinical improvements in the severity of the eczematous lesions. Lamb meat is also of special interest in infant nutrition because it provides a somewhat unique fatty acid (FA) profile that mirrors what is thought to be optimal for neonatal growth and development. However, very little is known about how the processing of fresh meat (FM) into prepared infant foods influences its FA composition. In this study, we compared the FA profile of FM from suckling lambs with those of homogenized (HO) and lyophilized (LIO) baby foods prepared primarily with lamb meat. The results show that the content of total omega-3 polyunsaturated FAs was the highest in FM (more than 3-fold) compared to commercial baby food, due to largely higher contents of α-linolenic acid (1.5-fold higher), eicosapentaenoic acid (6-fold higher), and docosahexaenoic acid (10-fold higher). Furthermore, arachidonic acid was more than 6-fold higher in FM compared to LIO and HO. Results from this study suggest the possibility of enhancing the FA profile of commercial baby food based on meat by using lamb meat, but care should be taken during processing so that important FAs are not lost. PRACTICAL APPLICATION: In this article, we have documented that meat from the suckling lamb is an interesting and potentially important source of omega-3-FAs, especially some of the long-chain polyunsaturated FAs (LC-PUFAs) that are essential for optimal neonatal growth and development. These results may have special implications to the infant food industry, in that products made using meat from suckling lambs may provide not only exceptional amounts of these FAs, but also other limiting essential nutrients such as iron. This may be especially important in regions of the world, such as Italy, where use of lamb meat as a weaning food is common during infancy.