Variation in the composition of Cretan avocado cultivars during ripening

The effect of ripening on the chemical characteristics of fruits of the avocado (Persea americana) cultivars Ettinger, Fuerte and Hass was investigated. A study of some quality parameters of these main avocado cultivars grown on the island of Crete was performed. As the fruit ripened, a decrease in the moisture content was observed, with a high degree of correlation for all the cultivars. At the same time an increase in the fat and protein contents was measured. The content of total sugars was high in the unripe fruit but decreased during ripening. The fatty acid composition of the oil extracted from the fruit pulp was determined by gas chromatographic analysis. The oil of the edible portion of the fruit was rich in oleic, palmitic, linoleic and palmitoleic acids, while stearic acid was present in small quantities. During the ripening process the amount of palmitic acid decreased and that of oleic acid increased in all the cultivars. The ratio of polyunsaturated to saturated fatty acids, which is considered as an indicator of the nutritional value of the fruit, was also calculated. No significant differences were observed between the cultivars. Principal component analysis was also performed to examine the relationship among the quality variables of the cultivars. From these data, Fuerte was considered to be the cultivar with the best characteristics. Copyright © 2004 Society of Chemical Industry     

Effect of variety and crude protein content on nutrients and certain antinutrients in field peas (Pisum sativum)

Protein content was used as an indicator of environmental conditions for a study on varietal and environmental variation in proximate composition, minerals, amino acids and certain antinutrients of field peas. Four field pea varieties, each with three levels of protein content, were selected. Crude protein content overall ranged from 20.2 to 26.7%. Analysis of variance showed that both variety and environmental conditions had a significant effect on starch, acid detergent fibre (ADF), neutral detergent fibre (NDF) and fat content, but ash content was only affected by variety. Significant varietal and environmental differences in potassium (K), manganese (Mn) and phosphorus (P) were noted. Calcium (Ca) and copper (Cu) showed significant varietal differences, while iron (Fe), magnesium (Mg) and zinc (Zn) had significant environmental differences. Environmental conditions showed significant effects on alanine, glycine, isoleucine, lysine and threonine content. Variety had a significant effect on sucrose, raffinose and phytic acid content, whereas environmental conditions had an influence on trypsin inhibitor activity (TIA). The major pea components protein and starch were inversely correlated. ADF, NDF, Fe, Mg, Zn and the amino acid arginine were positively correlated with protein content. The amino acids glycine, histidine, isoleucine, lysine and threonine were negatively correlated with protein content. It was found that tryptophan was the most deficient amino acid and the sulphur‐containing amino acids were the second limiting amino acids in peas. Raffinose was positively correlated with sucrose but negatively correlated with verbascose. There were significant correlations between mineral contents and some of the proximate components. Copyright © 2004 Society of Chemical Industry     

Content of some antinutritional factors in bean cultivars frequently consumed in Brazil

Protein content and content of some antinutrients were determined in four Vigna unguiculata (L) Walp and three Vicia faba cultivars frequently consumed in Brazil. The V. faba cultivars showed higher protein contents [26.8%–27.2% (w/w)] than the V. unguiculata cultivars [20.5%–22.5% (w/w)]. The difference was, however, not statistically significant (P ≥ 0.05). Compared with the V. unguiculata cultivars, the V. faba cultivars exhibited a significantly higher content of all antinutritional factors analysed. In V. faba, condensed tannins ranged from 1.95 to 2.87 g eq. catechin (CE) kg⁻¹, polyphenols from 4.81 to 7.21 g kg⁻¹, phytate from 12.7 to 14.3 mmol kg⁻¹, trypsin inhibitor activity from 4.12–4.38 TIU mg⁻¹ and haemagglutinating activity from 51.3 to 57.2 HU kg⁻¹; whereas in V. unguiculata, the corresponding values were determined to be 0.97–1.81 g eq. CE kg⁻¹ for condensed tannins, 5.87–6.62 g kg⁻¹ for polyphenols, 8.7–12.6 mmol kg⁻¹ for phytate, 3.09–3.56 TIU mg⁻¹ for trypsin inhibitor activity and 0.5–0.6 HU kg⁻¹ for haemagglutinating activity.     

Assessment of the effect of condensed (acacia and quebracho) and hydrolysable (chestnut and valonea) tannins on rumen fermentation and methane production in vitro

BACKGROUND: Tannins added to animal diets may have a positive effect on energy and protein utilisation in the rumen. The objective of this study was to examine the impact of different sources and concentrations (20, 50, 100, 150 and 200 g kg^?1 dry matter (DM)) of condensed (acacia and quebracho) and hydrolysable (chestnut and valonea) tannins on rumen microbial fermentation in vitro. The experiment also included a negative control with no tannins (control) and a positive control with monensin (10 mg L^?1). RESULTS: In vitro gas production and total volatile fatty acid (VFA) concentration decreased as tannin concentration increased. Addition of acacia, chestnut or valonea tannins at ≥ 50 g kg^?1 or quebracho tannins at ≥ 100 g kg^?1 resulted in a decrease (up to 40%) in methane (CH₄) production compared with the control. Valonea tannins were the only tannin source that reduced (?11%) CH₄ production at 50 g kg^?1 without affecting VFA concentration. Tannin treatments reduced ammonia (NH₃) and branched‐chain VFA concentrations, indicating a reduction in ruminal protein degradation. Monensin reduced CH₄ production (?37%) and NH₃ concentration (?20%) without affecting total VFA concentration. CONCLUSION: Supplying acacia, chestnut or valonea tannins at 50 g kg^?1 has the potential to reduce CH₄ production and ruminal protein degradation with minimum detrimental effects on efficiency of ruminal fermentation. Copyright © 2012 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Effect of enzymatic treatment on tannins and phytate in sorghum (Sorghum bicolor) and its nutritional study in rats

Sorghum is a cereal used as a food source by humans and animals. However, it presents antinutritional factors such as tannins and phytic acid, compounds that form complexes with proteins and minerals, respectively, decreasing sorghum’s digestive value. The purpose of this study was to apply tannase and phytase to sorghum and evaluate the effect on tannins and phytate level and the effect of the enzymatic treatment on Wistar rats. Tannin sorghum was treated with tannase and phytase, the effect of this treatment was measured in a study with rats, a group received a diet with raw sorghum and the other one a diet with treated sorghum. The enzymatic treatment was effective in reducing tannins and promoting the increase of inorganic phosphorus. The biological assay showed that the enzymatically treated sorghum was better than raw sorghum in the apparent digestibility of phosphorus, in the level of glucose, cholesterol and triacylglycerol. Treatment of the sorghum also resulted in lower activity of the enzymes aspartate aminotransferase and alanine aminotransferase in rat serum. The enzymatic treatment of sorghum could improve the nutritional value of this cereal while also decreasing environmental pollution.     

Trans Fatty Acid Contents in Selected Dietary Fats in the Estonian Market

In response to public concern, this study assessed the fatty acid (FA) composition of blended spreads, margarines and shortenings in the Estonian retail market in 2011. Special attention was paid to the trans fatty acids (TFA) composition. The changes in these characteristics of selected dietary fats in the market over recent years are also presented. Twenty-six edible fat brands, available in the Estonian retail market in 2011, were purchased and FA compositions were analyzed by chromatography. Saturated fatty acids (SFA) were the dominant group of FAs for all blended spreads (49.6 to 65.8%), and for the majority of shortenings (from 21.1 to 54.6%). Cis monounsaturated fatty acids (MUFA) were the dominant group of FAs for the majority of margarines, ranging from 25.3% to 50.5%. The total TFA for blended spreads varied from 1.18% to 9.08%, for margarines from 0.04% to 34.96% and for shortenings from 0.14% to 39.50%. Octadecenoic (C18:1) isomers were the main TFA found. Compared to 2008/2009, the industrially produced TFA (IP-TFA) content in several of the dietary fat brands was much reduced in 2011. This voluntary reformulation was probably a response to consumer demand associated with a public health campaign directed against IP-TFA in Estonian foods, and were mainly achieved by replacing TFA with SFA C12:0-C16:0. Practical Application: Present paper is directed toward public health related institutions and food industries producing foods with potentially high contents of trans fatty acids (TFA). According to the public concern TFA content in domestic blended spreads has declined significantly over the past 3 y in Estonia. The reduction in the TFA content was achieved by replacing TFA with saturated fatty acids (SFA) (C12:0-C16:0). To shift food composition toward healthier product formulations, mandatory labeling of the sum of IP-TFA and SFA (C12:0-C16:0) was recommended.     

香蕉单宁的提取、结构及功能研究进展

单宁作为植物多酚家族的一员,具有抗氧化、抗肿瘤和抗炎症等生理活性,被广泛应用于食品、医药和制革等行业中。香蕉是“世界四大水果”之一,被证明含有丰富的单宁,但鲜有关于香蕉单宁近年来研究进展的总结。因此,本文对香蕉单宁的提取、结构及功能研究进展进行系统性综述。目前,关于香蕉单宁提取工艺的研究主要围绕溶剂提取法、超声波辅助提取法、微波辅助提取法和酶辅助提取法展开,化学结构研究包括对其分子质量分布、聚合度范围、主要化学组成、结构单元及其连接方式的阐明,而功能活性研究则集中在评价香蕉单宁的抗氧化、抗菌、降血脂、降血糖、降低农药对机体毒性、结合金属离子和吸收紫外线等方面的作用。最后,对香蕉单宁今后的研究方向趋势提出展望,以期为扩大其在食品行业中的应用提供一定的理论指导。     

Modulation of chelating factors,trace minerals and their estimated bioavailability in Italian and African sorghum (Sorghum bicolor (L.) Moench) porridges

Factors able to modulate chelating factors, trace minerals and their bioavailability were investigated in porridges of five sorghum (Sorghum bicolor (L.) Moench) varieties: from Nigeria, Senegal, Burkina Faso and two from Italy. Effects of variety and traditional fermentation and cooking were assessed on iron‐binding phenolic groups, phytates and iron and zinc content and bioavailability. Chelating factors, trace elements as well as the effect of processing (mainly fermentation) were modulated by variety. Fermentation decreased iron‐binding phenolic groups until 49% and phytate content until 72% as well as increased phytase activity 3.4–16.4 fold, leading to enhancement of iron and zinc estimated bioavailability. Cooking alone had almost no effect. The lowest chelating factors content and the highest trace minerals bioavailability were shown by fermented Senegal landrace, whereas the Italian varieties overall showed the worst results. The results indicate that selection of traditional varieties and appropriate processing methods can improve sorghum nutritional value.     

Effect of tea saponins on milk performance,milk fatty acids,and immune function in dairy cow

This study investigated the effects of tea saponins (TSP) on milk performance, milk fatty acids, and blood immune function in dairy cows. A total of 20 early-lactation Holstein cows (days in milk = 66.4 ± 16.8 d; parity = 1.75 ± 0.91; and milk yield = 36.3 ± 7.32 kg/d; mean ± standard deviation) were randomly divided into 4 homogeneous treatment groups, with TSP added at 0, 20, 30, and 40 g/d per head, respectively. All cows had 2 wk of adaptation and 6 wk of treatments. Feed, milk, and blood were sampled and analyzed weekly. At the end of the experimental period (wk 6), the dry matter intake and yields of energy-corrected milk, milk, and milk protein, fat, and lactose in the cows fed TSP showed a quadratic response, with the lowest values in cows fed TSP at 40 g/d. The milk fat content of cows fed TSP increased linearly. Significant interactions for treatment by week were found in milk C16:1 cis-9 and C18:1 cis-9, with the highest values at wk 2, 3, and 4 in the cows fed TSP at 40 g/d. The levels declined quickly after 4 wk of feeding to values similar to those for other TSP treatments and the control at wk 5 and 6. Plasma malondialdehyde concentration decreased as the supplement level of TSP increased. The concentration of superoxide dismutase increased as the supplement level of TSP increased. The plasma concentration of tumor necrosis factor-α increased as the supplement level of TSP increased. In summary, this study showed that an intermediate dose of TSP (20 and 30 g/d) had no significant effect on feed intake, but the supplementation of 40 g/d TSP decreased feed intake, resulting in a lower milk yield. The energy-corrected milk of cows fed 40 g/d TSP declined at first but increased after 3 wk of feeding, indicating the potential adaptation to high doses of TSP supplements in dairy cows. The supplementation of TSP could reduce oxidative stress in cows and improve the immunity of dairy cows during 6 wk of feeding.     

Protein,amino acid and fatty acid contents in raw and canned sea urchin (Paracentrotus lividus) harvested in Galicia (NW Spain)

Moisture, protein, amino acid and fatty acid contents of raw and canned sea urchin (Paracentrotus lividus) gonads were determined. Sea urchin showed a high moisture content (73%) and a high level of proteins (56% dry matter). The canning process, evaluated at 112 °C for 50 min, did not lead to significant changes in protein, amino acid and fatty acid contents relative to the raw sample. © 2000 Society of Chemical Industry     

Composition, structure and absorption of milk lipids: a source of energy, fat-soluble nutrients and bioactive molecules

Milkfat is a remarkable source of energy, fat-soluble nutrients and bioactive lipids for mammals. The composition and content of lipids in milkfat vary widely among mammalian species. Milkfat is not only a source of bioactive lipid components, it also serves as an important delivery medium for nutrients, including the fat-soluble vitamins. Bioactive lipids in milk include triacylglycerides, diacylglycerides, saturated and polyunsaturated fatty acids, and phospholipids. Beneficial activities of milk lipids include anticancer, antimicrobial, anti-inflammatory, and immunosuppression properties. The major mammalian milk that is consumed by humans as a food commodity is that from bovine whose milkfat composition is distinct due to their diet and the presence of a rumen. As a result of these factors bovine milkfat is lower in polyunsaturated fatty acids and higher in saturated fatty acids than human milk, and the consequences of these differences are still being researched. The physical properties of bovine milkfat that result from its composition including its plasticity, make it a highly desirable commodity (butter) and food ingredient. Among the 12 major milk fatty acids, only three (lauric, myristic, and palmitic) have been associated with raising total cholesterol levels in plasma, but their individual effects are variable-both towards raising low-density lipoproteins and raising the level of beneficial high-density lipoproteins. The cholesterol-modifying response of individuals to consuming saturated fats is also variable, and therefore the composition, functions and biological properties of milkfat will need to be re-evaluated as the food marketplace moves increasingly towards more personalized diets.     

Variability in oil content and fatty acid composition of Ethiopian and introduced cultivars of linseed

This study was undertaken to assess the variability in oil content, oil yield and fatty acid composition of 60 linseed cultivars and to identify suitable accessions for use in future breeding and development endeavours in Ethiopia. Mean oil contents ranged from 291 to 359 g kg^?1, while oil yields varied between 1443 and 3276 g m^?2. Exotic introductions, especially those from Canada such as CDC‐VG, had higher oil contents than the local cultivars. Thus the introduction of exotic materials should be given more emphasis through germplasm exchange programmes. Unsaturated fatty acids were the major components in the oils, varying significantly (P < 0.01) from 859 to 906 g kg^?1, while minor saturated fatty acids were present at 84–119 g kg^?1. The contents of oleic, linoleic and linolenic acids were 148–293, 109–161 and 470–591 g kg^?1 respectively. Although accessions with variable linolenic acid contents were identified, this variability was insufficient to develop genotypes with less than 20 g kg^?1 linolenic acid for cooking oil through conventional crossing and selection methods. Hence mutation techniques and the introduction of exotic lines should be regarded as alternative approaches to obtain linseed genotypes with low linolenic acid contents. Copyright © 2004 Society of Chemical Industry     

铁皮石斛花营养成分分析

目的 明确铁皮石斛花的营养价值, 促进其开发利用。方法 以烘干后的铁皮石斛花为原料, 采用国家标准方法测定铁皮石斛花的蛋白质、可溶性糖、多糖、游离氨基酸总含量, 应用高效液相色谱法、气相色谱-质谱法、液相色谱-质谱法和电感耦合等离子体发射光谱法检测游离氨基酸、可溶性糖、中长链脂肪酸、维生素和矿物质含量。结果 铁皮石斛花中游离氨基酸和可溶性糖含量分别为(2.37±0.07)%和(45.74±1.77)%, 从铁皮石斛花中检测到16种氨基酸、13种可溶性糖、12种矿质元素、8种脂肪酸、10种B族维生素以及维生素E、维生素C和维生素K1。结论 铁皮石斛花富含亚油酸 (16.09±0.45) mg/g、VB4(530.78±29.37) μg/g、VC(201.28±0.01) μg/g和K(18289.63±1398.96) mg/kg等多种营养物质, 可作为功能食品的开发原料。     

Supplementing fresh pasture with maize,lotus, sulla and pasture silages for dairy cows in summer

A trial was conducted to compare benefits obtained from feeding four types of silage. There were two silages that contained condensed tannins (CT)—lotus (Lotus corniculatus) and sulla (Hedysarum coronarium)—maize silage or traditional ryegrass pasture silage, all fed at 5 kg dry matter (DM) cow^?1 day^?1 with restricted pasture (RP). Cows on the RP (control) treatment and those fed the silage treatments were offered an allowance of 25 kg pasture DM cow^?1 day^?1, while the full pasture (FP) cows were offered 50 kg pasture DM cow^?1 day^?1. Silage supplementation increased both DM intake and milk yield compared with cows given RP only. Cows on the lotus silage supplement and the FP treatment had significantly higher milk production than the other silage supplemented cows (P < 0.001). For cows given lotus silage, the high milk yield was probably due to a combination of the higher nutritive value of the silage and possibly to the protein‐sparing effects of the lotus condensed tannins because the total DM intake of cows fed the lotus silage was the same as that of cows given the pasture and maize silages (P > 0.25). The high milk yield of the FP treatment was mainly a result of the cows having a higher intake of pasture than cows on all the other treatments. This study demonstrated the potential benefit of silage supplementation, particularly with lotus silage, for increased milksolids yield in summer when low pasture growth rates and quality may otherwise limit production. Copyright © 2006 Society of Chemical Industry