发酵金鲳鱼糜制品工艺条件的优化及发酵过程中品质变化分析

以金鲳鱼糜为主要原料,毛霉为发酵菌种,通过单因素试验得到发酵金鲳鱼糜制品的最佳主发酵工艺条件,同时研究发酵过程中蛋白酶活性、理化指标及质构特性等的变化。实验结果表明：金鲳鱼糜制品最佳发酵工艺条件为：发酵时间为48 h、发酵温度为26 ℃、毛霉菌悬液接种量为5%。在发酵过程中金鲳鱼糜制品的水分含量逐渐降低,发酵到48 h时,水分降低到49.08%;pH由6.86降低到6.23;总酸由0.03%增高到0.51%;挥发性盐基氮由1.16 mg/100 g增加到20.57 mg/100 g,相对于对照组来说明显降低;氨基酸态氮由0.04%上升到0.51%;蛋白酶活力从0上升到65.05 U/g。发酵过程中金鲳鱼糜制品的硬度呈先升高后降低的趋势,发酵结束后硬度为248.36 g;胶黏性呈现先升高后降低再升高的趋势,发酵结束后胶黏性为18.15,明显低于对照组;弹性呈逐渐降低的趋势（48 h后达到0.63）,但是较对照组高;咀嚼性呈先降低后升高而后趋于平稳的趋势,发酵结束后咀嚼性为264.58,明显高于对照组。从最终产品质量来看,金鲳鱼糜制品发酵后品质明显提高。为发酵金鲳鱼糜食品的开发奠定了一定了理论和技术基础。     

抑菌流化冰提高白鲳鱼的贮藏品质

为了提高冰鲜海鱼的品质,对比研究了3种抑菌物质二氧化氯(Cl O2)、乳酸链球菌素(Nisin)和二甲基二碳酸盐(DMDC)制备的流化冰在24天贮藏期内对白鲳鱼品质特性的影响。结果显示:在平均温度为1℃的贮藏环境中,随着冰鲜时间的延长,白鲳鱼的TVB-N值和TBARS值升高,升高幅度显著小于普通流化冰(p<0.05),TVB-N值显示Cl O2样品24 d为33.47 mg/mL,DMDC样品20 d为34.45 mg/mL,Nisin样品16 d为37.41 mg/mL,普通流化冰样品12 d为39.53 mg/mL,抑菌流化冰延长了白鲳鱼的货架期。抑菌流化冰可以促进白鲳鱼鱼肉p H值、硬度、弹性和色度等的稳定性,证明Cl O2抑菌流化冰样品的新鲜度保持更好。通过研究白鲳鱼在不同贮藏环境中的品质变化,建立微生物学Logistic模型能够较准确地预测白鲳鱼在冰鲜保藏温度-1至5℃的货架期,其相对误差范围不超过3.22%。研究结果有助于提高白鲳鱼等海洋鱼在贮藏期间的品质,延长其货架期。     

银杏叶提取液与竹醋液流化冰对鲳鱼冰藏期间品质变化的影响

研究银杏叶提取液流化冰与竹醋液流化冰对鲳鱼冰藏期间品质变化的影响。将新鲜鲳鱼运至实验室,清洗后随机分组,分别用体积分数1%银杏叶提取液与体积分数1%竹醋液制得的流化冰进行冰藏处理,以普通流化冰处理后的样品为对照组。贮藏期间,分别于第0、5、9、12、15、18天进行各组样品的感官、理化(质构、电导率、pH值、K值、硫代巴比妥酸值、挥发性盐基氮(total volatile basis nitrogen,TVB-N)含量)与微生物(菌落总数、假单胞菌总数和希瓦氏菌总数)指标分析,并结合低场核磁共振技术对冰藏鲳鱼品质变化的影响进行综合评价。结果得出:与对照组相比,银杏叶提取液和竹醋液流化冰处理组均能较好保持样品的感官品质与质构特性,延缓其电导率值、pH值、K值、TVB-N含量与微生物指标的上升,减慢鱼肉的氧化速率。银杏叶提取液与竹醋液流化冰处理能使鲳鱼的冰藏期从9~12 d分别延长至15~16 d和17~18 d。     

茶多酚和EGCG对风干金鲳鱼品质相关理化指标的改善效果比较

为比较分析茶多酚及茶多酚的主要成分表没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）对风干金鲳鱼加工过程中品质相关的理化性质的改善作用,在腌制液（8%的食盐溶液）中分别添加0.05%茶多酚、0.05%EGCG和0.02%EGCG,对腌制和风干过程中鱼肉的盐含量、持水率、水分迁移、硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARS）值和挥发性盐基氮（total volatile basic nitrogen,TVB-N）值进行检测,并通过气相色谱-离子迁移谱分析风干金鲳鱼加工过程中挥发性风味物质的变化规律。结果显示,添加茶多酚和EGCG均可有效抑制鱼背肉和鱼腹肉腌制和风干过程中TVB-N值和TBARS值升高（P<0.05）,通过减少不易流动水的损失提升鱼肉的持水性,其中0.05%茶多酚改善效果最佳,其次是0.05%EGCG,最后是0.02%EGCG。风干金鲳鱼加工过程中共鉴定出63种挥发性成分,其中醛类、酮类及酯类物质随着腌制风干工艺的进行呈上升趋势,形成风干金鲳鱼独特的风味。添加茶多酚...     

三种植物源防腐剂对鲳鱼保鲜效应的影响

以八角茴香、大蒜、茶多酚等3种植物源防腐剂处理鲳鱼。通过感官指标、pH值、挥发性盐基氮（TVB—N）、菌落总数及抑菌圈的测定,来评价鲳鱼冷藏过程中的品质变化。结果表明,这3种植物源防腐剂的提取液都具有一定的保鲜效果。其中,在5℃条件下,对照组即经蒸馏水处理过的鲳鱼能放置3d左右。荼多酚与大蒜的效果较为相近,能够放置约4．5d,而经茴香提取液处理的鲳鱼能够放置4d左右。     

Shelf life extension of Atlantic pomfret (<Emphasis Type="Italic">Brama brama</Emphasis>) fillets by packaging under a vacuum-skin system

The present study was aimed at improving the commercialisation strategies of Atlantic pomfret (Brama brama), a medium-size fish commonly consumed as fresh fish. With this purpose, an innovative vacuum-skin packaging system including a surface thermal treatment was tested on Atlantic pomfret fillets stored at 4 °C for up to 19 days. The results were compared with traditional vacuum packaging carried out in parallel. The investigation of three sensory features (flesh appearance, flesh odour and flesh colour), five biochemical parameters (pH, free fatty acids, conjugated dienes, fluorescent compounds and total volatile bases) and three microbiological parameters (aerobic mesophiles, anaerobes and coliforms) was carried out in both batches. The vacuum-skin packaging system showed an interesting preservative effect leading to a significantly higher quality retention and longer shelf life (12 days) with respect to both traditional vacuum packaging (7 days) and a control batch kept in air (5 days). From the results obtained, it is concluded that the vacuum-skin system allows an extended shelf life and a better maintenance of the sensory, biochemical and microbiological quality of Atlantic pomfret fillets. This innovative packaging system might be applied to other kinds of fish species to stimulate the marketing opportunities.     

不同冷藏期鲳鱼及草鱼气味变化分析

以鲳鱼和草鱼分别作为海水鱼和淡水鱼代表,利用电子鼻评价冷藏条件下不同贮藏期的鱼肉气味,并通过气相色谱-质谱检测挥发性风味成分的变化。结果表明,电子鼻可以较好区分不同贮藏期的鱼肉气味,且草鱼的气味变化较鲳鱼更为显著。贮藏期间鲳鱼和草鱼分别鉴定出22 种和19 种挥发性物质,主要包括醛类、醇类、酯类及腐败性化合物等。新鲜鲳鱼挥发性风味主要以1-戊烯-3醇、己醛、1-辛烯-3醇、庚醛、2-辛烯醛为主,草鱼以己酸甲酯为主。贮藏期间,鲳鱼和草鱼气味成分变化也具有差异性,鲳鱼中和腐败相关的化合物主要为三甲胺和3-甲基丁醇等,且贮藏过程中醛类、醇类均呈下降趋势;草鱼贮藏过程中的第2天及第4天较为相关的化合物为癸醛、1-辛烯-3醇、己醛和壬醛等脂肪氧化的产物,而贮藏后期与腐败相关的化合物较少。上述结果初步说明生长环境、脂肪氧化及微生物腐败影响了海鱼和淡水鱼冷藏期气味形成。     

Formation mechanism of nano-scale antibiotic and its preservation performance for silvery pomfret

To improve the antibacterial stability, a self-assembly method was applied. The typical antibiotic of nisin was loaded in chitosan nanoparticles (Nano-N) which was used as a carrier of antibiotics. The characteristics and formation mechanism of nano-scale antibiotic as well as its preservation properties on silvery pomfret were investigated. The results exhibited that the nano-scale antibiotics were nearly sphere-like with the mean size of 150 nm. The formation of nano-scale antibiotics was attributed to interactions among the functional groups of chitosan, sodium tripolyphosphate and nisin by hydrogen bonds and electrostatic interactions. Meanwhile, the preservation effects to silvery pomfret by the nano-scale antibiotic coatings were better than nisin or chitosan nanoparticle coating alone, which was ascribed to a more efficient prevented oxygen, microorganism as well as protein degradation from silvery pomfret by the self-assembled nano-scale antibiotic coating. Thus, it could extend the shelf life of fish by 3 d–9 d, suggesting that nano-nisin coating have great potential in the seafood preservation field.     

模拟物流运输条件下冻半干金鲳鱼品质和风味变化

目的:探究半干金鲳鱼在模拟实际运输温度下的品质和风味变化。方法:以冻半干金鲳鱼为研究对象,模拟其在不同温度下的物流运输过程,测定了解冻损失率、肌原纤维蛋白构象的变化、蛋白质和脂质氧化等理化指标以及风味物质的变化规律。结果:半干金鲳鱼的蛋白质和脂质氧化程度均随运输时间的延长显著升高(P<0.05),且温度越高氧化程度越显著(P<0.05),此过程中蛋白质发生聚集且变性程度严重,而解冻损失率仅随温度升高显著增大(P<0.05)。共检测出17种氨基酸,总氨基酸、鲜味氨基酸和苦味氨基酸含量随着运输时间的延长均呈先显著上升后下降的趋势(P<0.05),温度对其含量则无显著影响(P>0.05)。半干金鲳鱼的主要挥发性物质为醛类、烃类和醇类,其中高温运输组的醛类含量显著下降,而烃类物质含量显著上升(P<0.05)。结论:冻半干金鲳鱼在较低温下运输能够减缓蛋白质的变性程度以及蛋白质和脂质氧化程度,并使其富有更多良好的风味物质。