桑椹多酚对广式腊肠贮藏过程中脂质降解和氧化特性的调控作用

脂质氧化和水解是形成腊肠特征风味的重要途径,但过度氧化会造成腊肠品质的劣变。桑椹多酚是一类天然抗氧化剂,被证实可以有效缓解腊肠储藏过程中的氧化反应,然而其通过调控腊肠脂质氧化和水解来改变腊肠风味的相关机制还鲜有研究报道。鉴于此,该研究将桑椹多酚提取物（1 g/kg）加入到肉糜中,制成广式腊肠,跟踪28 d的储藏过程中腊肠的脂质氧化代谢产物（共轭二烯、共轭三烯、TBARS和己醛）以及脂肪酸（中性脂肪酸、游离脂肪酸和磷脂）的组成变化。研究发现,桑椹多酚主要通过抑制脂质次级代谢产物（己醛和丙二醛）来延缓腊肠的脂质氧化。经过28 d的储藏期后,桑椹腊肠中己醛与丙二醛的含量较对照组分别下降63.10%与28.05%。此外,储藏过程中桑椹多酚还可以有效抑制腊肠储藏过程中游离脂肪酸、磷脂的释放。经过28 d的储藏期后,与对照组相比,桑椹腊肠的游离脂肪酸含量下降了9.59%。同时,桑椹多酚还可以减少风味物质中醛类物质的产生和积累。综上所述,桑椹多酚主要通过延缓腊肠储藏过程中脂质的降解及次级氧化过程来调控产品的风味。     

天然抗氧化剂对亚麻籽甘油二酯油氧化稳定性的影响

为提高亚麻籽甘油二酯油的氧化稳定性,研究了抗坏血酸棕榈酸酯、迷迭香提取物和维生素E及其组合对亚麻籽甘油二酯油的抗氧化作用。以氧化诱导时间为响应值,在单因素实验基础上,通过响应面分析确定最优的抗氧化剂组合。考察了优化的抗氧化剂组合对亚麻籽甘油二酯油高温加热时反式脂肪酸含量的影响。结果表明：相较于单一的维生素E、迷迭香提取物和抗坏血酸棕榈酸酯,三者组合能显著提高亚麻籽甘油二酯油的氧化稳定性;最优抗氧化剂组合为抗坏血酸棕榈酸酯添加量84 mg/kg、迷迭香提取物添加量405 mg/kg、维生素E添加量1 808 mg/kg,在此条件下亚麻籽甘油二酯油的氧化诱导时间为11.13 h,是空白对照的6.79倍;该抗氧化剂组合能抑制油中反式脂肪酸的生成。天然抗氧化剂绿色、安全,可有效提高亚麻籽甘油二酯油的氧化稳定性。     

Correlation of viscoelastic behavior with water state and ultrastructure in hot air-dried carrots

This study evaluated and correlated the viscoelastic behavior, water state and ultrastructure of hot air-dried carrots. The results revealed that with increasing time, hot air-drying increased loss tangent (Tan δ) and reduced storage (G′) and loss (G″) moduli, cell wall components including total pectin (Tp), hemicellulose (He), and cellulose (Ce), free water (reflected by relaxation time T₂₃ and relative area M₂₃) in vacuoles, and immobilized water (T₂₂ and M₂₂) in cytoplasm and extracellular space in carrots. Pearson's correlation analysis showed that G′ and G″ were positively correlated (p < 0.01) with T₂₂, T₂₃, M₂₃, Tp, He, and Ce in dried carrots, whereas Tan δ was negatively with these indicators (p < 0.01). Principal component regression analysis revealed that the contribution rate of principal factor 1 and 2 (F1 and F2) was 72.7 and 21.9%, respectively. The Tp, He, Ce, T₂₃, and M₂₃ (42.3, 42.7, 42.5, 43.8 and 44.2% of the explained variance, respectively) were well explained by F1. The G′, G″, and Tan δ could be predicted by the following regression equation, G′ = 0.696 × F1, G″ = 0.680 × F1, and Tan δ = 0.341 − 0.652 × F1. These relationships were consistent with the more pronounced changes (plasmolysis of cytoplasm, disruption of plasmalemma and tonoplast, and degradation of cell walls and middle lamella) in the ultrastructure of dried carrots.     

桑椹多酚及其微胶囊对猪肉脯品质的改良

该实验使用超声法将桑椹多酚(MP)包埋入 β-环糊精中(β-CD),制备桑椹多酚-β-环糊精微胶囊(MPM),验证了 β-环糊精对桑椹多酚的保护作用,并探究了桑椹多酚对肉脯的理化特性、抗氧化活性以及氧化稳定性的影响.结果表明,β-环糊精可以提高酚类物质的稳定性,实现酚类物质的缓释.添加有0.2％MPM的肉脯在贮藏28 ...     

植物资源在改善肉类预制菜肴品质中的应用前景

肉制品是人类重要的蛋白质来源。肉类预制菜肴的加工和贮藏过程中容易发生过氧化反应与微生物污染,造成营养流失、色泽衰退、风味下降。传统肉制品抗氧化剂对人体健康带来的安全隐患问题已引起人们重视,天然植物资源在调控肉制品营养与品质中的应用备受关注。天然植物中富含多酚、多糖、有机酸、萜类化合物等活性成分,对于肉制品的色泽、氧化、风味及有害物质生成等均具有良好调控作用。该研究围绕着肉类预制菜肴关键的品质变化、植物中典型的活性物质、天然活性物质在肉类预制菜肴中的应用现状这三个方面进行综述,并对当前植物资源在改善预制菜肴品质中存在问题和未来发展方向进行分析,为肉类预制菜行业高质量发展提供参考。     

不同品种苦瓜多糖含量及其抗氧化和α-葡萄糖苷酶抑制活性比较

为比较不同苦瓜品种果肉多糖的含量和组成差异,以及抗氧化能力和α-葡萄糖苷酶抑制活性,研究选用13个苦瓜品种为材料,分析其多糖、糖醛酸、蛋白质含量及分子量分布,并采用总抗氧化能力指数评价其抗氧化活性,4-硝基酚-2-D吡喃葡萄糖苷(PNPG)法测定其α-葡萄糖苷酶抑制率,同时分析组成和活性的关系。研究结果表明13个品种苦瓜果肉中多糖、糖醛酸、蛋白质含量分别介于5.91~10.62%(干重),25.21~42.37%和3.17~4.60%;苦瓜果肉多糖均包含了2个主要组分,重均分子量(Mw)分布分别为1558.88~3048.56 kDa和33.19~58.74 kDa;ORAC指数变幅为19.39~57.73μmol Trolox/g;α-葡萄糖苷酶最大抑制活性变幅为4.80~92.67%;ORAC指数与多糖、己糖醛酸和蛋白含量均呈显著正相关(P0.05)。不同苦瓜品种间多糖的含量组成、抗氧化能力和α-葡萄糖苷酶抑制活性存在显著基因型差异,多糖是抗氧化活性的主要贡献物质,并且己糖醛酸与蛋白质可以增加其抗氧化能力。     

不同工艺山茶油在储藏过程中品质变化

旨在为山茶油的加工和储藏提供参考,采用Schaal烘箱法对4种工艺山茶油加速氧化,测定山茶油在储藏过程中酸值、过氧化值、p-茴香胺值、脂肪酸、甘油酯以及脂质伴随物的变化情况,并对山茶油质量指标与脂质伴随物进行Pearson相关性分析。结果表明：4种工艺山茶油在储藏过程中的酸值略微升高,上升为初始值的1.09～2.60倍;过氧化值、p-茴香胺值迅速上升,分别上升为初始值的10.31～16.49倍和3.06～4.43倍;α-生育酚含量大幅度下降,损失率为96.19%～100.00%,而角鲨烯、植物甾醇含量下降幅度不大,损失率分别为14.71%～51.79%和4.96%～19.49%,其中浸出-精炼山茶油的脂质伴随物含量最低,损失较多;由Pearson相关性分析可知,山茶油的质量指标(酸值、过氧化值、p-茴香胺值)与其α-生育酚含量呈显著或极显著负相关。综上,不同工艺山茶油的品质和营养价值在储藏过程中均明显下降,浸出-精炼山茶油的储藏稳定性不如压榨山茶油。     

Lychee (Litchi chinensis Sonn.) seed water extract as potential antioxidant and anti-obese natural additive in meat products

The antioxidative properties of lychee seed water extract (LSWE) in raw meat paste during a storage period of 0–15 days at 4 °C were evaluated. The cytotoxic effects and the anti-obese effects of LSWE were evaluated using an in vitro 3T3-L1 preadipocyte cell model. The sensory properties of the cooked meat paste supplemented with different amount of LSWE were also evaluated. Results showed that LSWE was non-toxic and effective in inhibiting preadipocyte differentiation. These effects were attributable to down-regulation of several adipogenesis-specific genes, i.e., PPAR γ, C/EBP α, C/EBP β, C/EBP δ, and KLF9. Supplementation with LSWE was also effective in retarding lipid oxidation of meat paste. Sensory evaluation indicated that LSWE did not adversely affect the sensory properties of the meat paste. On the contrary, LSWE significantly improved the sensory properties of the meat paste during the late stage of the storage period. Based on the results, LSWE was determined to be effective in inhibiting adipogenesis and retarding lipid oxidation, which can improve the safety and quality of meat products.     

草菇对牛肉蛋白结构的修饰效应

该研究以牛肉糜及其蛋白为对象,比较了草菇粉（5%,m/m）处理前后牛肉肉糜的理化性质、蛋白溶解性、肌原纤维蛋白的结构、聚集状态及流变特性等的变化,以解析草菇对牛肉糜品质的影响机理。结果显示：草菇会有效降低肉糜的蒸煮损失率,但造成肉糜的pH值和挥发性盐基氮含量提高,产品色泽变暗。其中,草菇处理48 h后肉糜样品蒸煮损失最低（3.44%）,较对照组减少约4.48倍。与此同时,随着处理时间的延长,蛋白溶解性先降低后增加,肌原纤维蛋白的羰基化及巯基向二硫键的转化程度逐渐提高,α-螺旋的含量由34.50%降低至29.50%。草菇处理后,蛋白质的降解与聚集程度提高,凝胶流变性能得到显著改善。上述研究结果表明,草菇中的内源成分可能通过促进蛋白质氧化和水解,来影响肉糜制品的风味和质构等品质。该研究结果有助于解析食用菌对肉制品品质的影响机理,并为食用菌在新型风味肉制品开发中的应用提供理论依据。     

Continuous quality and shelf life monitoring of retail-packed fresh cod loins in comparison with conventional methods

This study investigated the applicability of a new photochromic time-temperature indicator (TTI) to monitor the quality and shelf life of fresh cod loins in retail packs at different storage conditions; also compared this automatic monitoring method with other methods of quality control, such as sensory, chemical and microbiological analyses; and with a shelf life prediction model. TTI placed on the bottom of the packs effectively reflected the temperature condition of the product. TTI with the initial square value of 61 was suitable for continuous monitoring of the quality and shelf life of the product repacked on day 6 after processing. The estimated product shelf lives based on TTI and on the square-root model for relative rate of spoilage of fresh seafood were well correlated.