UV-absorbing compounds and susceptibility of weedy species to UV-B radiation

Stratospheric ozone (O₃) depletion has led to increased terrestrial ultraviolet‐B (UV‐B) radiation (290–320 nm). Leaves exposed to this radiation produce UV‐absorbing compounds in the epidermal cells, which protect plants from UV‐B damage. To determine the role of UV‐absorbing compounds in the UV‐B sensitivity of weeds (common chickweed (Stellaria media), downy brome (Bromus tectorum), green smartweed (Polygonum scabrum), redroot pigweed (Amaranthus retroflexus), spotted cat’s‐ear (Hypochoeris radicata), and stork’s‐bill (Erodium cicutarium)) seedlings were exposed to 0, 4 (field ambient), 7 (18% O₃ depletion) and 11 (37% O₃ depletion) kJ m^?2 d^?1 of biologically effective UV‐B radiation in a greenhouse. Ultraviolet‐absorbing compounds were extracted from the second true‐leaf (0.5 cm² samples) with methanol : distilled water : HCl (79 : 20 : 1) in an 85°C water bath for 15 min, and the absorbance of the extracts measured at 300 nm. The shoot dry biomass was recorded to determine the susceptibility to UV‐B radiation. Common chickweed was the most sensitive and green smartweed the least sensitive weed to UV‐B radiation. The latter accumulated more UV‐absorbing compounds and this accumulation occurred earlier compared with common chickweed. As UV‐B_BE radiation levels increased from 0 to 11 kJ m^?2 d^?1, the green smartweed shoot biomass did not decline. However, the biomass of all five susceptible species declined despite an increase in the UV‐absorbing compounds in response to increased UV‐B radiation. Therefore, formation of a ‘UV‐screen’ in these species is not sufficient to fully prevent UV‐B damage. When the concentration of UV‐absorbing compounds in the six species was plotted against their susceptibility to UV‐B radiation, no relationship was observed. Thus, while the accumulation of UV‐absorbing compounds may be a major factor in the protection of certain species against UV‐B radiation and may offer some degree of defence in other species, it does not explain UV‐B susceptibility differences in weedy species in general.     

套袋对鸭梨果实香气及糖酸组分的影响

采用静态顶空和气相色谱-质谱联用技术、高效液相色谱技术,研究了生长期套袋对鸭梨果实挥发性成分、糖酸组分等风味物质的组成和含量的影响。结果表明:套袋导致鸭梨香气物质种类减少和相对百分含量降低。套袋鸭梨采收时测定的香气成分有3类18种,其中酯类15种、烯类2种、醇类1种;不套袋鸭梨采收时测定的香气成分有3类26种,其中酯类23种、烯类2种、醇类1种。鸭梨的主要香气成分是乙酸己酯、己酸乙酯、丁酸乙酯。套袋和不套袋鸭梨均检测到3种糖、4种有机酸组分,其中糖组分主要为果糖,其次为蔗糖、葡萄糖,有机酸组分主要为苹果酸,其次为乙酸、柠檬酸、草酸,但不同处理间含量存在差异。     

Volatile profile,fatty acids composition and total phenolics content of brewers' spent grain by-product with potential use in the development of new functional foods

Brewers' spent grain (BSG) is the insoluble residue generated from the production of wort in the brewing industry. This plant-derived by-product is known to contain significant amounts of valuable components, which remain unexploited in the brewing processes. Therefore, it is essential to develop a more detailed characterization of BSG in order to highlight its potential in developing new value-added products and simultaneously solve the environmental problems related to its discharge. The content of BSG in several biologically active compounds (fatty acids, polyphenols, flavonoids, antioxidant capacity) as well as its volatile fingerprint were assessed and compared with the composition of barley, malt and wheat flour samples. The obtained results emphasized the importance and the opportunities of the re-use of this agro-industrial by-product.     

Effects of artificial light sources on accumulation of phytochemical contents in hydroponic lettuce

Lettuce is grown in different parts of the world and it is beneficial for health. Light condition is one of the most important environmental factor in regulating growth, development, and phytochemical accumulation in lettuce, particularly when lettuce is produced in a hydroponic system. Due to advances in technologies, artificial light sources have become increasingly capable of providing appropriate quality, intensity, and photoperiod of light in hydroponic lettuce production. This review highlights the progress of current research on the effects of artificial light regulation on growth and phytochemical accumulation in lettuce produced in hydroponic systems.     

Relevance of Osmotic and Frost Protecting Compounds for the Winter Hardiness of Autumn Sown Sugar Beet

The cultivation of autumn sown sugar beet (winter beet) is supposed to result in a marked yield increase compared with spring sown sugar beet. Although the importance of the growth stage reached before winter for the survival of autumn sown sugar beet has already been shown, it is not clear to which extent osmotic and potentially frost protecting compounds may contribute to winter hardiness. The study thus aimed to analyse the acclimatization process of sugar beet to low temperatures and to identify compounds which are important for survival of frost. Field trials with autumn sown sugar beet were conducted at eleven environments in Germany from 2009/10 to 2012/13, which were accompanied by greenhouse experiments with controlled temperature regimes. In the field trials, the survival rates after winter varied from 0 % to 99 %, but only in four environments differences between the five genotypes occurred. During acclimatization, betaine, glutamine, proline and raffinose were markedly accumulated and osmolality was enhanced. In particular betaine, amino acids and osmolality showed a positive correlation to the survival rate and were thus identified as potentially frost protecting substances for sugar beet. In contrast, raffinose and proline seem to act rather as stress indicators as they were negatively related to survival. Possible frost protecting substances were identified which can be used in breeding to improve the winter hardiness of sugar beet.     

Productive and biochemical responses of durum wheat to UV filtration

A UV exclusion experiment was conducted on durum wheat (Triticum durum Desf. var. Claudio) grown in pots. Plants were grown under three different radiative treatments in greenhouses covered with plastic filters: Teflon, transparent to the entire region of natural UV‐visible sunlight (TEF); polyester, transparent above 312 nm (MYL, excluding UVB) and Lee, transparent above 400 nm (LEE, excluding both UVA and UVB). Analyses have been carried out to determine the concentration of photosynthetic pigments in leaves, UV‐absorbing compounds, nitrogen and carbon in leaves, culms and spikes and proteins and gluten in grains. In particular, plants grown under UV exclusion showed a reduction in protein and dry gluten content (consequently without variation in the ratio dry gluten/protein), but at the same time, a significant increase of gluten index, which is a parameter to define the quality of gluten, was observed. The results highlighted the influence played by UV radiation on some biochemical parameters, mainly UV‐absorbing compounds, leaf nitrogen and grain protein characteristics of durum wheat cultivated under Mediterranean conditions. In particular, natural level of UV in the Mediterranean improves the characteristics of durum wheat flour important for pasta production (high dry gluten level), while the UV exclusion could improve characteristics of flour important for bread production (high gluten index).     

水产调味品鲫鱼汁的研制

随着人们生活水平的提高,对食品质量的要求也在不断的提高,调味品在食品质量中扮演着非常重要的角色。本实验以普通养殖鲫鱼为主要原料,研究水产调味品鲫鱼汁的最佳工艺。通过正交试验和感官评价,最终得到水产调味鲫鱼汁的最佳配方:黄原胶0.04%,鲫鱼汁30%,盐15%,糖5%,谷氨酸钠5%,5′-肌苷酸0.25%,叶黄素0.03%,鱼味香精0.03%,山梨酸钾0.05%,均质压力35MPa。水产调味品鲫鱼汁质地均匀,口感细腻,鱼鲜风味突出,色泽淡黄,气味芬芳,符合人们对于风味和营养的需求,具有广阔的市场前景。     

4份桃种质挥发性成分的GC-MS分析

为了分析桃果实中共有的挥发性成分及初步探讨果皮毛和果肉颜色性状对挥发性成分的影响情况,以此2对性状均存在差异的4份桃种质为试材,采用顶空固相微萃取方法提取其成熟果肉中的挥发性成分,并用气相-质谱联用仪对其进行了测定。结果表明:4份桃种质中共鉴定出116种挥发性成分,其主要为酯、醛、醇和烷烃等类物质。从挥发性成分的种类数量上看,白肉桃‘大久保’和‘华光’中检出的挥发性成分种类较多,分别有68和52种;而2份黄肉桃种质中检出的挥发性成分种类均较少。从挥发性成分的种类上看,2份普通桃与2份油桃中的差异挥发性成分总共仅有3种,其分别为反式-2,4-庚二烯醛、戊酸-2,2,4-三甲基-3-异丙酸-异丁酯和脱氧精胍菌素,远低于2份白肉桃与2份黄肉桃种质中差异挥发性成分的数量(13种)。此外,从挥发性成分的类群上看,2份白肉桃含有较多的"青香型"的C6类化合物,而2份黄肉桃含有较多的"果香型"的酯和内酯类化合物。文中综合分析认为,果皮毛的有无和果肉的颜色性状均可能影响果实中挥发性成分的数量和种类,但后者的影响较为明显。     

Nutritive value of sorghum silage for sheep

This study compared ensiled sorghum (ES) from two varieties (first and second cuts) with corn silage (CS) for chemical analysis, total-tract nutrient digestibility, ruminal variables and blood biochemistry metabolites in sheep. Five experimental silages representing first cut ES var. Pegah (PS1), second cut ES var. Pegah (PS2), first cut ES var. Speedfeed (SS1), second cut ES var. Speedfeed (SS2) and CS were assessed for chemical analysis, silage fermentation and anti-quality compounds. Diets consisted of lucerne hay, silage and a premix (at the ratio of 53.5:46:0.5 on a dry matter [DM] basis). Feed consumption, total-tract nutrient digestibility, microbial nitrogen supply (MNS), ruminal variables and blood biochemistry metabolites were determined in a Latin square design of five periods with five male sheep. Compared to sorghum, CS had lower (p < 0.01) concentrations of ash, water-soluble carbohydrates and crude protein, but higher starch, lignin (sa), non-structural carbohydrates and apparent nutrient digestibility. The measurements of pH, lactic acid, NH₃-N and volatile fatty acids (VFA) confirmed that all silages were well-preserved. The anti-quality compound levels in the silages were below the safe limits for ruminants. No differences were observed in feed consumption (p > 0.05) and total-tract digestibility of DM and nutrients (p > 0.05). Rumen pH, NH₃-N, VFA concentrations and acetate to propionate ratio showed no difference among treatments (p > 0.05). Sheep fed on sorghum silage showed a decrease (p < 0.01) in total protozoa, and particularly in the Entodiniae population. There were no differences in cellulolytic bacteria counts (p > 0.05) among treatments. Urinary N, MNS and blood biochemistry metabolites showed no difference among treatments (p > 0.05). Silages from both cuts of sorghum had comparable total-tract nutrient digestibility to CS, therefore, these varieties could be used as a more drought resilient silage source in the feeding of sheep.