3种富硒菊花的化学成分及其对α-葡萄糖苷酶活力的影响

为了探究富硒菊花的食用安全性与营养保健功效,给富硒菊花种质资源选育和开发利用提供依据。本研究采用全自动氨基酸分析仪等分析了金丝菊、香菊、雪菊3种富硒菊花的营养组成,采用高效液相色谱法测定了9种酚类、黄酮类化合物的含量,采用原子荧光光谱法等测定了重金属含量,分析了富硒菊花的抗氧化活性及其对α-葡萄糖苷酶的抑制效应。结果发现,3种菊花的硒元素含量在0.125 9～0.195 4μg/g之间。雪菊的水分、灰分含量最高,金丝菊的粗脂肪含量最高,香菊的总蛋白、清蛋白和球蛋白含量最高,同时具有较高的必需氨基酸化学评分和氨基酸评分,说明香菊的氨基酸组成与人体需求较为接近。3种菊花均含有3-咖啡酰奎宁酸、4,5-二咖啡酰奎宁酸、木犀草苷、芹菜苷、蒙花苷、木犀草素、芹菜素、香叶木素和金合欢素,均未检出镉与汞,铜、砷和铅含量分别在13.250～20.875μg/g、0.000～0.087μg/g、0.375～1.038μg/g之间。富硒菊花具有一定的总还原力与DPPH·、ABTS·+、·OH自由基清除活性,能够抑制α-葡萄糖苷酶的活力。本研究为富硒菊花种质资源选育和开发利用提供了参考依据。     

断奶对仔猪肠道屏障的影响及营养调控

在集约化养殖中,3~4周龄早期断奶是仔猪生命周期中一个非常紧张的时期,此时仔猪胃肠道还未发育成熟。肠道屏障由上皮、免疫和肠神经系统组成,这些系统控制上皮屏障的完整性以及肠道功能,包括肠腔营养物质、水和电解质的运输。早期断奶导致肠道通透性增加,出现胃肠功能紊乱的情况,可能对猪只一生产生长期的影响。因此,仔猪断奶饲粮需要正确水平的营养素、营养源和高质量的添加剂,鼓励仔猪快速进食,减轻或消除断奶应激综合症,降低死亡率和发病率。养猪就是养"肠道",合理使用功能性氨基酸、植物化学物质和有机酸等添加剂,能够修复由于断奶应激综合症导致的肠道屏障功能障碍。     

Conversion of starch from dry common beans (Phaseolus vulgaris L.) to ethanol

Dry common beans (Phaseolus vulgaris L.) were evaluated for potential conversion of starch to ethanol. Eight varieties of beans with average starch content of 46% (db) were assayed in a laboratory-scaled process based upon the commercial corn dry grind fermentation process. Ethanol yield was 0.43-0.51 g ethanol/g glucose (0.19-0.23 g ethanol/g beans). The average ethanol yield for the eight bean types was 92% of maximum theoretical yield, demonstrating that starch from beans could be efficiently converted to ethanol. Ethanol concentration obtained from 20% (w/w) solids loading was 3.5-4.4% (w/v). The residual fermentation solids contained, on a dry basis, 37.1-43.6% crude protein, 10.8-15.1% acid detergent fiber and 19.1-31.3% neutral detergent fiber.     

发酵豆制品中主要植物化学成分及生理功能的研究进展

发酵豆制品是亚洲国家人民饮食中重要的组成部分,并逐渐得到国际上的广泛关注和西方国家的青睐。豆制品本身含有丰富的植物化学成分,在微生物的发酵过程中这些植物化学成分衍生出许多具有生物活性的物质,这些物质对人体的生理功能产生一定的影响。为发酵豆制品的发展寻找新的方向,综述了近年来豆制品在发酵过程中植物化学成分的变化以及对豆制品生理功能的影响。     

Variation of wheat grain lipid fraction and its antioxidative status under the impact of delayed sowing

This study determined the profile of hydrophobic phytochemicals (steroid-like components and lipophilic phenolics) and antioxidant potential (DPPH and Rancimat tests) of wheat grain in relation to sowing date (standard vs. delayed) using six cultivars of Triticum aestivum wheat grown in Poland. The study found that “sowing time” generally had a low impact on sterols, carotenoids, squalene and total lipophilic phenolics in wheat grain. The highest impact of “sowing time” was noted for α-tocopherol, C19:0 alkylresorcinol and campesterol. Delayed sowing reduced their content by up to 9%. The antioxidant potential of grain extracts obtained by the use of water-saturated butanol (WSB) was mostly cultivar-dependent (depending on assay: DPPH 56.3% and Rancimat 75.1% of explained variation, respectively). Wheat grain WSB extracts increased rapeseed oil induction time by up to 21% and their antioxidant capacity was up to 1.24 μM TEg⁻¹.     

Whole grain phytochemicals and health

Phytochemicals and antioxidants in whole grains have not received as much attention as the phytochemicals in fruits and vegetables although the increased consumption of whole grains and whole grain products has been associated with reduced risk of developing chronic diseases such as cardiovascular disease, type 2 diabetes, some cancers and all-cause mortality. Recent research has shown that the total phytochemical content and antioxidant activity of whole grains have been commonly underestimated in the literature, and that whole grains contain more phytochemicals than was previously reported. Most whole grain phenolics are in bound form, 85% in corn, 76% in wheat, and 75% in oats. In addition, whole grains contain unique phytochemicals that complement those in fruits and vegetables when consumed together. The beneficial effects associated with whole grain consumption are in part due to the existence of the unique phytochemicals of whole grains. The majority of phytochemicals of whole grains that are beneficial for health are present in the bran/germ fraction. In whole wheat flour, the bran/germ fraction contributed 83% of total phenolic content, 79% of total flavonoid content, 78% of total zeaxanthin, 51% of total lutein, and 42% of total β-cryptoxanthin. The bran/germ fraction of whole wheat may therefore impart greater health benefits when consumed as part of a diet, and help reduce the risk of chronic diseases. This paper will review recent research on the phytochemicals and antioxidant activity of whole grains and their unique contribution to the health benefits of whole grains.     

Amaranth (Amaranthus hypochondriacus) as an alternative crop for sustainable food production: Phenolic acids and flavonoids with potential impact on its nutraceutical quality

The demand for food is increasing, not only to meet food security for growing populations, but also to provide more nutritious food, rich in good quality proteins and nutraceutical compounds. The amaranth (Amaranthus hypochondriacus) plant, in addition to its high nutritive and nutraceutical characteristics, has excellent agronomic features. The objective of the present study was to analyze some physical and proximal-nutritional properties of amaranth seeds obtained from different varieties grown in arid zones and characterize their phenolic acids and flavonoids. Two commercial (Tulyehualco and Nutrisol) and two new (DGETA and Gabriela) varieties of A. hypochondriacus were grown at the Mexican Highlands zone. Tulyehualco and DGETA varieties had higher seed yield of 1475 and 1422 kg ha⁻¹, respectively, comparable to corn and soybean production in agricultural areas. Gabriela had the highest protein content of 17.3%, but all varieties had an adequate balance of essential amino acids. Polyphenols as rutin (4.0–10.2 μg g⁻¹ flour) and nicotiflorin (7.2–4.8 μg g⁻¹ flour) were detected. Amaranth can be cultivated in arid zones where commercial crops cannot be grown; the seeds besides their well known nutritive characteristics could be a source of phenolic compounds of high antioxidant properties.     

Antifeedant activity and toxicity of leaf extracts from <Emphasis Type="Italic">Porteresia coarctata</Emphasis> Takeoka and their effects on the physiology of <Emphasis Type="Italic">Spodoptera litura</Emphasis> (F.)

Antifeeding and toxic effects of chemical extracts from Porteresia coarctata Takeoka on the insect pest Spodoptera litura (F.) were investigated in the laboratory. Hexane extracts of P. coarctata leaves were re-dissolved in dimethyl sulfoxide and applied in water to leaves of Ricinus communis L. (castor). A concentration of 1,000 and 2,000 ppm extract exhibited significant antifeeding and toxic effects to third instar larvae when compared to the same concentration of dimethyl sulfoxide in water as control. One day after feeding on extract-treated castor leaves, the mortality of S. litura larvae was 50%. Mortality increased to 95% after 11 days at a dosage of 2,000 ppm. Compared to the control, third instar larvae fed on castor leaves treated with P. coarctata leaf extract at different concentrations showed significant reduction in protein and DNA content in the fat body and midgut tissues. Results demonstrate the insecticidal and antifeedant properties of P. coarctata leaf extract against the generalist pest S. litura leading to biochemical changes in the insect body. Thus, P. coarctata contains phytochemicals, and the extract, in crude and pure form, has potential as a botanical insecticide in alternative control strategies against Lepidoptera pests.     

Quantification of phenolic acids and antioxidant activity in sweetpotato genotypes

Phenolic acid composition and antioxidant activity in roots of 14 commercially important sweetpotato genotypes were evaluated. Significant differences in total phenolics, individual phenolic acids, and antioxidant activity were found among the different sweetpotato genotypes. Total phenolic content, expressed in terms of chlorogenic acid equivalent, in different genotypes ranged from 1.4 to 4.7 mg g⁻¹ dry weight (DW). Antioxidant activity was evaluated as Trolox equivalent, ranging from 1.3 to 4.6 mg g⁻¹ DW. The highest total phenolic content and antioxidant activity were observed in a purple-fleshed genotype. Chlorogenic acid and 3,5-dicaffeoylquinic acid were the predominant phenolic acids, while caffeic acid was the least abundant in most genotypes. The highest content of chlorogenic acid (422.4 μg g⁻¹ DW) was present in a white-fleshed cultivar ‘Quarter Million’ imported from Jamaica. However, a purple-fleshed genotype had the highest amounts of 3,5-dicaffeoylquinic (485.6 μg g⁻¹ DW), 3,4-dicaffeoylquinic (125.6 μg g⁻¹ DW), 4,5-dicaffeoylquinic (284.4 μg g⁻¹ DW), and caffeic (20.5 μg g⁻¹ DW) acids.     

Baby-leaf and multi-leaf of green and red lettuces are suitable raw materials for the fresh-cut industry

Consumer demand for softer leaves with variation in taste, shape and colours has encouraged the development of new lettuce products of baby-sized leaves. The objective of this study was the comparison of whole-head lettuce, as the most common raw material for fresh-cut, with baby-leaf and multi-leaf as the newest baby-sized lettuce leaves. Lettuces (Lactuca sativa L.) of the types Green Leaf, Red Leaf and Lollo Rosso were cultivated in the same field with different plant densities, under commercial conditions. Although baby-leaf was subjected to far less wound damage than the shredded lettuce from the whole-head, leaf age could play an important role in increasing respiration rate and determining postharvest quality. After 9-11 d of storage, minimally processed products from the three types of raw material showed good visual quality without differences among them. However, over the 12-d storage period, quality decreased to the limit of marketability mainly due to browning of the cut edge surface of the fresh-cut product from whole-heads and decay due to the soft tissue in the case of baby-leaves. Additionally, with the processing of whole-heads, the increase in cut-damage surfaces and availability of cell nutrients provided conditions that favoured the growth of lactic acid bacteria (LAB) and total coliforms compared to uncut surfaces of baby-sized leaves. The ratio between the oxidized and reduced forms of ascorbate (DHA/AA) increased 2-4 times after 9-11 d of storage. Furthermore, baby-sized leaves had higher phenolic contents than the shredded product from the whole-head which probably contributed to reaching a shelf-life of 11 d. In conclusion, the new green and red baby-sized leaves both at immature and mature stages provided high quality lettuce for the fresh-cut market, meeting specific requirements regarding visual quality, microbial load and high content of phytochemicals.