添加枸杞副产物对紫花苜蓿青贮发酵品质及微生物多样性的影响

本试验旨在研究宁夏地区枸杞副产物对苜蓿青贮品质及微生物多样性的影响,为提高苜蓿青贮品质和寻找优质饲料添加剂提供科学依据。紫花苜蓿分别与0（CK）、40（T₁）、60（T₂）、80（T₃） g·kg^-1枸杞副产物混合青贮,发酵60 d后测定青贮营养成分、发酵品质及微生物多样性。结果表明：枸杞副产物处理组相比对照组,显著降低了酸性洗涤纤维含量（P<0.01）,显著提高了多糖含量（P<0.01）;对照组pH值及氨态氮/总氮分别为4.91、8.58%,苜蓿青贮中pH、氨态氮及乙酸含量随枸杞副产物比例增加而显著降低（P<0.01）,乳酸含量及乳酸乙酸比显著增加（P<0.01）;此外,枸杞副产物提高了青贮有氧稳定性,其中T₁及T₂处理组有氧稳定性较高。苜蓿青贮优势菌属主要为乳杆菌属、魏斯氏菌属和片球菌属,枸杞副产物降低了苜蓿青贮中乳杆菌属的相对丰度,增加了魏斯氏菌属及片球菌属的相对丰度。综上所述,枸杞副产物可改善苜蓿青贮发酵品质,提高有氧稳定性,改变微生物群落结构,且枸杞副产物添加量为60 g·kg^-1的处理组青贮发酵效果优于其他添加量。     

Recovery of Proteolytic and Collagenolytic Activities from Viscera By-products of Rayfish (Raja clavata)

The aim of this work was to study the recovery of proteolytic and collagenolytic activities from rayfish (Raja clavata) viscera wastes. Initially, different parts of the gastrointestinal tract by-products (stomach, duodenum section including pancreas, final intestine) were evaluated. The extracts from proximal intestine yielded the highest values of both enzymatic activities. Optimal conditions for protease activity quantification were established at pH = 6, T = 40 °C and incubation time ≤20 min. The mathematical equation used to model the joint effect of pH and temperature led to maximum activity at pH = 8.66 and 59.4 °C, respectively. Overcooled acetone was found to be best option for recovery of enzymatic activities in comparison with ethanol, PEG-4000, ammonium sulphate and ultrafiltration system. Finally, a simple and systematic protocol of partial purification and total recovery of proteases and collagenases was defined.     

Protease-induced solubilisation of carbohydrates from brewers' spent grain

The impact of microbial proteases on the release of carbohydrates from BSG was studied. The proteases were able to release the non-cellulosic glucose, a portion of feruloylated arabinoxylan and over 50% of the protein from brewers' spent grain (BSG) after 24 h hydrolysis. The non-cellulosic glucose was derived from residual starch-derived products persisting in BSG after mashing. The proteases did not cleave the hydroxycinnamate ester linkages present on the arabinoxylan backbone, and thus do not behave as feruloyl esterases. However, the material solubilised from spent grain by the proteases contained up to 198 μg bound ferulic acid/g extract, which represented 8.6% of the total ferulic acid present in BSG. These results suggest that a portion of water-extractable feruloylated arabinoxylan and starch is trapped within the BSG matrix by a proteinaceous barrier.     

A method for the detection of bromate in brackish water

The objective of this study was to develop a simple yet accurate method for the detection of bromate in brackish water. Typically, bromate is measured by ion chromatography; however, the presence of chloride ions complicates bromate detection using this technique. Where bromide ions are naturally present in the source water to be ozonated, either for drinking water or aquacultural purposes, bromate is formed as a disinfection by-product. As such, the need to measure bromate in brackish water is complicated due to the naturally present chloride ions. The study was carried out in a laboratory setting using a UV-spectrophotometer and an ion chromatograph to verify the results. To examine the robustness of the UV-based method, seven water matrices were used to test the bromate detection method. The bromate method presented herein utilizes a reaction of bromate with iodide followed by detection at a UV absorbance at 352 nm. A key finding from the study was that the concentration of bromate was quickly and accurately determined using spectrophotometry. This method successfully measured bromate in waters containing a broad range of conductivity and avoided interference from other anions. The method detection limit reported for all seven water matrices tested was greater than 0.14 mg L⁻¹, which limits the methods utility to saline solutions.     

利用酶解和发酵技术从淡水鱼副产物中提取多肽螯合钙的研究现状

淡水鱼加工过程中会产生40%~60%的副产物,该副产物的综合利用已成为亟待解决的重要问题。本文综述了淡水鱼副产物的营养价值和加工利用现状、钙的作用及补钙制剂种类、多肽螯合钙的螯合机制及结构分析以及利用酶解和发酵技术从淡水鱼副产物中提取多肽和多肽螯合钙的研究现状。同时提出了利用酶解和发酵技术从鲶鱼副产物中提取多肽螯合钙的研究思路与方法,以期为淡水鱼副产物的综合利用提供参考借鉴。     

Use of fermented milling by-products as functional ingredient to develop a low-glycaemic index bread

Selected Lactobacillus plantarum DSM 32248 and Lactobacillus rossiae DSM 32249, isolated and identified from wheat germ, were used to ferment a milling by-products mixture. Lactic acid bacteria metabolisms improved the functional properties of wheat bran and germ, which are considered important sources of functional compounds. Wheat breads were manufactured using 15% (w/w) of fermented (and unfermented) milling by-products, and compared to baker’s yeast wheat bread manufactured without the addition of milling by-products. The use of the fermented ingredient improved the biochemical, functional, nutritional, textural, and sensory features of wheat bread, showing better performances compared to the solely use of wheat flour. Protein digestibility, nutritional indexes, and the rate of starch hydrolysis markedly improved using fermented milling by-products as ingredient. Enriched bread was also characterized by high content of dietary fibre and low glycaemic index determined in vivo.This study exploited the potential of fermented milling by products as functional ingredient. According to the Regulations the bread made under this study conditions can be defined as “high fibre content” and “low glycaemic index”. A number of advantages encouraged the manufacture of novel and healthy and functional leavened baked goods.     

Proximate Composition and Nutritional Profile of the Black Sea Anchovy (Engraulis encrasicholus) Whole Fish,Fillets, and By-Products

ABSTRACT

In this study, the proximate composition and nutritional profile of the Black Sea anchovy and its by-products were investigated. The total yield of by-products from anchovy was about 32% of the whole fish based on wet weight. The protein and fat contents of anchovy by-products were 13.39 and 10.02% for head, 16.47 and 15.50% for frame, and 12.05 and 23.90% for viscera, respectively. Significant differences were detected among the pH and color properties of anchovy whole fish, fillet, and by-products. Profiles of amino acids, fatty acids, and minerals of anchovy by-products showed they are rich sources of lysine (6–7% of total amino acids), leucine (5–6% of total amino acids), and a number of essential amino acid, polyunsaturated fatty acids (about 32–40% of total fatty acids), n-3 fatty acids (about 27–34% of total fatty acids), eicosapentaenoic acid + docosahexaenoic acid (about 26–32% of total fatty acids), and various minerals (P, Fe, Ni, Ca, Mn, Na, and Zn). These results revealed that anchovy by-products can be utilized for the production of value-added products such as protein powder, protein hydrolyzates, fish oils, and mineral supplements.     

Alfalfa, rice by-products and their incorporation for weed control in rice

Two alfalfa varieties, namely Rasen and Yuba , and rice by-products of Koshihikari ( Oryza sativa L. cv. Japonica ), including hull and bran were used for weed control in rice. Rasen and Yuba were sequentially evaluated to have the strongest allelopathic potential among eight common alfalfa varieties in Japan. Rasen , Yuba and rice by-products in a laboratory experiment exhibited suppression of emergence of lettuce ( Lactuca sativa L.), barnyardgrass ( Echinochloa oryzicola Vasing.), and monochoria ( Monochoria vaginalis Presl var. plantaginea Solms-Laub.). In a paddy field experiment, at 15 days after application, a dose of 1 ton ha⁻¹ of alfalfa, rice by-products and the incorporated alfalfa-rice by-products significantly inhibited weed growth and reduced weed species, except for rice bran. However, at 40 days after application, the greatest weed control was sequentially recorded with Yuba (95.2%), Rasen (90.5%) and the incorporated Rasen -hull (88.3%). Rice hull exhibited stronger (51.7%) weed control than the negligible weed control of rice bran (25.1%). Inhibition of both Rasen and Yuba on weed emergence after application became more vigorous, whereas those of rice by-products were gradually devitalized. Rasen had a maximum increase of rice yield (80.6%) compared to the control and it was slightly higher (9.6%) than the herbicide treatment. Findings showed that Rasen was the most promising material for weed control among those studied. Results denoted that weed control capability of allelopathic materials had an impetuous effect on rice growth and yield.     

Bispora sp. MEY-1 来源嗜酸果胶甲酯酶性质分析及其应用研究

食品加工副产物富含果胶类物质，果胶酶可以将其降解为果胶低聚糖，不仅可以有效控制果胶低聚糖的聚合度及结构，还能实现食品加工副产物废弃资源的再利用，创造新的经济效益。从嗜酸真菌Bispora sp. MEY-1克隆获得一个碳水化合物第8家族的果胶甲酯酶基因Pem8A，将其连接到表达载体pPIC9上，在毕赤酵母 GS115 中实现高效异源表达。对纯化后的重组蛋白PME8A的酶学性质进行测定，发现其最适温度为60 ℃，在55～80 ℃可保持80%以上的酶活；最适pH为3.5，在pH 2.5～5.0范围内维持50%以上的酶活，是真菌来源中少数的嗜酸果胶甲酯酶。用PME8A处理苹果渣、橘皮果胶粗提物后，去甲基化效果明显，使得Achaetomium sp. Xz8来源的内切多聚半乳糖醛酸酶PG8fn酶活分别提高了8.5倍和1倍，表现出很好的协同效应。研究证明果胶甲酯酶PME8A可以应用于从食品加工副产物生产果胶寡糖，为果胶低聚糖的获取提供了新的方法。     

甘蔗制糖副产物的开发与利用

甘蔗副产物主要指甘蔗制糖外的产物,为可再生资源,其产量极为丰富,可利用形式多样。如何合理开发甘蔗副产物的价值和潜力是值得我们探讨的课题,且对资源综合利用、生态环境保护和甘蔗业可持续发展也具有非常重要的现实意义。基于此,本文主要从蔗梢、蔗叶、蔗渣和糖蜜4个方面综述了甘蔗副产物的资源化利用现状,以期为其进一步的开发提供理论参考。