转双反义淀粉分支酶基因大米中蛋白质的营养价值评价

目的 对转双反义淀粉分支酶基因大米和亲本大米蛋白质的营养价值进行评价.方法 采用通用的非生物学评价方法,即化学评分、氨基酸评分、蛋白质消化率校正后的氨基酸评分、必需氨基酸指数、营养指数、氨基酸比值系数和氨基酸比值系数分,评价大米蛋白质的营养价值.结果 转基因大米和亲本大米的化学评分分别为62,59;氨基酸评分分别为75,62;蛋白质消化率校正后的氨基酸评分分别为65,56;必需氨基酸指数分别为79,80;营养指数分别为11,8;氨基酸比值系数分分别为76.7,67.0;氨基酸比值系数都是l.1.结论 转双反义淀粉分支氨基因大来中抗性淀粉含童显著提高,但并未影响到其自身蛋白质的营养价值.该转基因大米蛋白质的营养价值与亲本大米具有"实质等同性".     

三相卧螺法生产小麦淀粉工艺中轻相液蛋白质的营养学评价

将小麦面粉和谷朊粉中蛋白质的营养进行比较,评价了三相卧螺法生产小麦淀粉过程中的副产物轻相液中蛋白质的营养价值。结果表明：轻相液中蛋白质的氨基酸评分和化学评分均高于小麦面粉和谷朊粉,其中必需氨基酸指数（EAAI）、生物价（BV）、氨基酸比值系数分（SRCAA）、体外蛋白质消化率（IVPD）、蛋白质的效率比（PER）以及蛋白质消化率校正的氨基酸评分（PDCASS）分别为0.95、92.06、73.73、85.4%、1.89和0.43。同时,利用模糊识别法计算得到轻相液中蛋白质的贴近度为0.85,高于小麦面粉和谷朊粉。因此,轻相液中的蛋白质优于小麦面粉和谷朊粉中的蛋白质。     

品种和加工方式对双低菜粕有效能和氨基酸有效性的影响

用精确饲喂技术评价了3个品种的中国双低油菜和1个加拿大卡诺拉的脱脂种籽和商品饼粕的能量和氨基酸的有效性。结果表明,4个脱脂种籽的氮校正真代谢能和氨基酸真消化率没有差异（P＞0．05）;而4个商品饼粕的脱脂样品的氮校正真代谢能和氨基酸真消化率有极显著或显著差异。研究结果证实,不适当的加工方式不仅降低了氨基酸的有效性,而且影响家禽对能量的利用效率。     

中华鳖腿肉蛋白质体内外消化研究

通过测定氨基酸组成、体内外蛋白质消化率及经蛋白质消化率校正的氨基酸评分（protein digestibilitycorrectedamino acid scores,PDCAAS）等指标,评价热处理前后中华鳖腿肉蛋白质的营养价值。结果表明：中华鳖腿肉热处理前后必需氨基酸含量分别为36.84%、34.55%（以干质量计）,占氨基酸总量的41.12%、40.20%,其构成符合联合国粮农组织/世界卫生组织推荐的理想模式。热处理前,测得中华鳖腿肉蛋白质体外消化率为83.68%,体内消化率为95.05%;热处理后,测得其体外消化率为87.04%,体内消化率为96.18%,热处理后消化率显著提高（P＜0.05）。结合氨基酸评分及真实消化率,计算得到热处理前其PDCAAS为100%,由于蒸煮过程营养物质的流失,测得热处理后Trp氨基酸评分最低为80,热处理后其PDCAAS为76.94%。     

食品中蛋白质质量评价方法的研究进展

不同食物中蛋白质的种类和含量不同,其氨基酸组成及比例也不同,因而对满足人体营养需求的贡献不同。蛋白质作为食物最基本的营养成分,其质量直接影响着人体健康。在全球人口激增、资源有限的情况下,科学合理的蛋白质质量评价方法对于人类合理膳食、获取充足营养、有效开发新型蛋白质资源等是非常重要的。因此,本文综合分析了食品中蛋白质质量评价方法的发展,并对蛋白质消化率校正氨基酸评分(protein digestibility corrected amino acid score,PDCAAS)和可消化氨基酸评分(digestibility indispensable amino acid score,DIAAS)展开详细讨论,重点阐述这两种评价方法的应用状况、优势及局限性,以期为探索优质蛋白质来源、研究蛋白质互补和开发高质量蛋白食品提供理论依据。     

品种和加工方式对双低菜粕有效能和氨基酸有效性的影响_注

用精确饲喂技术评价了 3个品种的中国双低油菜和 1个加拿大卡诺拉的脱脂种籽和商品饼粕的能量和氨基酸的有效性。结果表明 ,4个脱脂种籽的氮校正真代谢能和氨基酸真消化率没有差异 (P >0 .0 5 ) ;而 4个商品饼粕的脱脂样品的氮校正真代谢能和氨基酸真消化率有极显著或显著差异。研究结果证实 ,不适当的加工方式不仅降低了氨基酸的有效性 ,而且影响家禽对能量的利用效率。     

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.     

鹰嘴豆蛋白质的营养学评价

采用碱溶酸沉法制备鹰嘴豆蛋白,测定体外消化率、分析氨基酸组成,并计算氨基酸评分,对鹰嘴豆蛋白质的营养学价值进行综合评价。鹰嘴豆蛋白体外模拟消化率为97.9%。鹰嘴豆蛋白含有18种氨基酸,总氨基酸含量为868.7 mg/g,必需氨基酸含量为353.1 mg/g,接近WHO/FAO推荐的理想蛋白质氨基酸组成(360 mg/g)。鹰嘴豆蛋白质氨基酸评分为60.5,蛋白质总体营养价值高于常见的谷薯类及杂豆类植物蛋白,营养价值较高,是仅次于大豆蛋白的杂豆类植物蛋白来源。     

紫苏籽蛋白质与氨基酸的含量测定及营养评价

为了研究紫苏籽的营养价值,测定了本研究所选育的高油、优质紫苏品系奇苏2号和奇苏3号中紫苏籽的蛋白质与氨基酸含量,评价其营养价值,并与其他高蛋白食品进行比较。结果发现:紫苏籽蛋白质含量和花生、核桃相当,高于鸡蛋和牛乳;氨基酸种类齐全,包括8种人体必需氨基酸,各必需氨基酸含量与鸡蛋相当,高于牛奶,是优质的蛋白质食品。进行氨基酸营养价值评价可得,除缬氨酸外,奇苏2号氨基酸评分、化学评分均高于奇苏3号,必需氨基酸指数也高于奇苏3号,奇苏2号的营养价值高于奇苏3号。奇苏2号中除蛋氨酸+胱氨酸外,其他必需氨基酸的氨基酸评分均高于FAO推荐值;化学评分均接近或超过鸡蛋蛋白,其中蛋氨酸+胱氨酸的氨基酸评分和化学评分均最低,分别为13.68%和8.40%,为奇苏2号的第一限制级氨基酸。     

豇豆籽蛋白的氨基酸含量与营养价值评价

主要用反相高效液相色谱法分析豇豆籽的氨基酸含量,碱提酸沉法提取豇豆蛋白质,并采用两步法进行体外消化试验,综合评价豇豆籽蛋白的营养价值.结果显示豇豆籽蛋白氨基酸含量为23.28%,氨基酸模式接近参考蛋白模式,蛋氨酸为第1限制性氨基酸,豇豆籽分离蛋白的消化率为96.15%±0.75%,与大豆分离蛋白97.42%±0.88%无显著差异.     

Assessment of Algerian sorghum protein quality [Sorghum bicolor (L.) Moench] using amino acid analysis and in vitro pepsin digestibility

To assess the protein quality and the nutritive value of seven Algerian local sorghum cultivars, the in vitro pepsin digestibility was determined, which ranged from 25.0% to 65.0%, and the amino acid composition of each cultivar was compared with other sorghum cultivars. In addition, the amino acid scores (AAS) and the protein digestibility-corrected amino acid scores (PDCAAS) were calculated. Relative to the WHO protein standard, most of the sorghum cultivars tested, scored very high AAS, with values ranging between 0.9 and 2.6 except for lysine, methionine and cysteine. The PDCAAS were high for Ain Salah cultivars AS1 and AS3, however, all other cultivars showed low values except for leucine. This study confirmed that in terms of both quantity and quality, sorghum proteins could serve as a source of essential amino acids and as a potential source of proteins in the future.     

Protein quality and amino acid profiles of fish products available in Poland

Chemical analyses were carried out on 18 of the most popular varieties of fish products in the Polish market (canned, smoked, salted and marinated fish of different species), produced by the largest manufacturers and distributors in the country. The contents of the nutritive substances in the fish products (proteins, amino acids, and fats) were determined. To assess the nutritional quality of proteins in these products, the protein digestibility was determined, which ranged from 77.0% to 98.7%, and the amino acid composition of each of these groups of products was compared with that of a standard protein recommended by the World Health Organization (WHO). In addition, protein digestibility-corrected amino acid scores (PDCAAS) were calculated. Relative to the WHO protein standard, most of the fish products tested scored very high, with values ranging between 0.9 and 1.0. This study confirmed that in terms of both quantity and quality, fish products in the Polish market could serve as a significant source of essential amino acids and that the sulphur-containing essential amino acids and lysine present in fish products could supplement the corresponding deficiency in plant proteins. However, it was also indicated that drastic thermal processes, such as sterilisation, could influence the protein digestibility.     

Study of the effect of using different levels of tahinah (sesame butter) on the protein digestibility‐corrected amino acid score (PDCAAS) of chickpea dip

This study was conducted to investigate the effect of using different proportions of tahinah (0–25%) on the protein digestibility‐corrected amino acid score (PDCAAS) of chickpea dip and to evaluate this parameter when chickpea dip is consumed with wheat bread. Protein quality was evaluated using the methods of amino acid score and true protein digestibility in weanling Sprague–Dawley rats. The levels of tahinah that provided the best true protein digestibility and protein digestibility‐corrected amino acid score were 20 and 25%. Values of true protein digestibility were significantly higher (P ≤ 0.05) than for the other types of chickpea dip (0.87 and 0.88 respectively). The consumption of wheat bread with chickpea dip led to a marked improvement in the true protein digestibility of the protein mixture (0.90); however, the protein digestibility‐corrected amino acid score did not change in the same manner owing to the relatively low amino acid score. It can be concluded that the addition of tahinah to chickpea led to an increase in the protein digestibility‐corrected amino acid score of chickpea dip (based on laboratory rat requirements for essential amino acids) and that the consumption of chickpea dip with bread led to an improvement in the protein digestibility of chickpea dip but not in the protein digestibility‐corrected amino acid score. © 2002 Society of Chemical Industry     

Proximate composition, fatty acid analysis and protein digestibility-corrected amino acid score of three Mediterranean cephalopods

Proximate composition, fatty acid analysis and protein digestibility-corrected amino acid score (PDCAAS) in three commercially important cephalopods of the Mediterranean sea (cuttlefish, octopus and squid) were determined. The results of the proximate analysis showed that these species had very high protein:fat ratios similar to lean beef. Docosahexaenoic, palmitic and eicosipentaenoic acid were the most abundant fatty acids among analyzed species. The amount of n-3 fatty acids was higher than that of saturated, monounsaturated and n-6 fatty acids. Despite the fact that cephalopods contain small amounts of fat they were found quite rich in n-3 fatty acids. Finally, PDCAAS indicated that these organisms had a very good protein quality.     

In-vitro protein and sulphur amino acid availability as a measure of bean protein quality

The total and ‘available’ cystine and methionine, and the in-vitro and in-vivo protein digestibilities were determined in six varieties of Phaseolus vulgaris with different seed coat colours. Reactive cystine and methionine, evaluated by chemical methods after in-vitro enzymic digestion, were taken as a measure of the availability of sulphur amino acids. Cystine ‘availability’ ranged from 43 to 51% and from 31 to 58% in raw and cooked samples, respectively, while methionine ‘availability’ was over 90%, except for the two red varieties (55% and 74%). No correlation was found between cystine and methionine ‘availability’ and in-vitro protein digestibility. In-vitro protein digestibility (76.6-80.7%) showed a good correlation (r = 0.857; P < 0.05) with in-vivo values (72.0-80.9%). Amino acid score corrected for protein digestibility and for sulphur amino acids availability, as suggested by the Codex Committee on Vegetable Proteins, seems to predict accurately the biological quality of bean protein, as was shown when in-vitro indices were compared with net protein utilisation and relative protein value.     

Protein digestibility‐corrected amino acid scores,acceptability and storage stability of ready‐to‐eat supplementary foods for pre‐school age children in Tanzania

This study was conducted to evaluate protein quality, acceptability and storage stability of processed cereal–bean–sardine composite foods for pre‐school age children in Tanzania. Four composite products namely corn–bean–sardine meal (CBSM), bean meal (BM), sorghum–bean–sardine meal (SBSM) and rice–bean–sardine meal (RBSM) were formulated to maximize the amino acid score for pre‐school age children and were processed by extrusion, drum‐processing and conventional cooking. The products were evaluated for true protein digestibility (TPD) and protein digestibility‐corrected amino acid score (PDCAAS). The TPD and PDCAAS were highest in the extruded products. The TPD values for the products ranged from 82 to 93%. The PDCAAS values for the composite foods were 64–86% and were greater than the minimum value of 60% recommended by FAO/WHO/UNU. There were no significant (p > 0.05) variations in the amino acid contents for foods processed by extrusion, drum‐processing or conventional cooking. Threonine was most limiting in the CBSM, SBSM and RBSM while methionine + cysteine were most limiting in the BM. Sensory evaluation showed that, relative to the traditional cornmeal—Uji, the extruded CBSM and SBSM had significantly superior (p ≤ 0.05) texture and highly acceptable color and taste. Storage of the products up to 16 weeks at 38 °C resulted in a small but significant increase (p ≤ 0.05) in the malondialdehyde concentrations; nevertheless, the levels remained within the acceptable range found in processed commercial supplements. Total acids, pH and organoleptic attributes did not change significantly (p > 0.05) during storage and the foods were acceptable to the end of the storage period. Copyright © 2005 Society of Chemical Industry     

Comparative study of phytic acid content,in-vitro protein digestibility and amino acid composition of different types of flat breads

Phytic acid content of eight different types of leavened and unleavened flat breads was determined. It was highest in unleavened and non-fermented whole wheat chapati and lowest in the leavened and fermented white wheat flat bread roghni nan. The effect of baking conditions, bread composition and phytic acid content on in-vitro digestibility of protein was measured using a pepsin multienzyme pH stat technique. The amino acids released were separated by ultrafiltration. The rate of protein digestibility of flat bread and amino acid released depended upon the type of flour used, baking conditions, phytic acid content and other antiproteolytic constituents of breads. Leavening and fermentation of breads resulted in an increase of protein digestibility and availability of amino acids. Addition of soya flour increases the protein digestibility of breads whereas millet flour decreases it.