Comparative Effects of Fish and Cow Gelatins and Locust Bean Gum on Chemical,Textural, and Sensory Properties of Yogurt

ABSTRACT

Yogurt is a traditional dairy product widely consumed all over the world. Syneresis, which is a result of lower water holding capacity, is a big concern and an important quality parameter. In this study, the efficiency of locust bean gum and different gelatins (fish skin, fish scale, and bovine skin) in preventing syneresis was investigated. Samples were stored at 4°C for 2 weeks, a typical shelf life of yogurt, and analyzed periodically for quality parameters. Syneresis, viscosity, and water holding capacity of the control and gum added samples were almost identical, while gelatin added samples were generally significantly improved (p < 0.05).     

The Effects of Fermentation Process with Acid and Lactic Acid Bacteria Strains on the Biogenic Amine Formation of Wet and Spray-Dried Fish Silages of Discards

The impacts of fermentation process with acid and lactic acid bacteria strains (Lactobacillus plantarum, Lactobacillus brevis, Pediococcus acidilactici, Enterococcus gallinarum, and Streptococcus spp.) on the biogenic amine formation of wet and spray-dried fish silage obtained from whole gibel carp (Carassius gibelio, freshwater discard), whole ponyfish (Equulites klunzingeri, seawater discard), and processing by-products of seabass (Dicentrarchus labrax) were investigated. The results showed that among biogenic amines, cadaverine, putrescine, spermidine, spermine, serotonin, dopamine, and agmatine were predominant in all groups. Significant differences (p < 0.05) in biogenic amine concentrations of wet and spray-dried fish silage were observed. Raw fish and wet silages contained histamine level lower than the allowable limit of 50mg/kg, indicating the use of raw fish material with low microbial counts. In addition, no histamine was detected in spray-dried fish silage, except for seabass by-products with a trace quantity of histamine (<0.04mg/100g). The starter culture used for silage preparation did not effectively retard formation of biogenic amines compared to acid silage. It can be concluded that there is potential use of fermented fish silage as a protein source and possibly as a probiotic ingredient for animal feed in both wet and dry form.     

Effects of Potassium Lactate and Acetate on Listeria monocytogenes Inhibition,Physicochemical and Sensory Properties of Smoked Catfish Fillets

The objective of this study was to evaluate the effects of liquid and wood smoking with a potassium lactate (PL) and acetate (PA) combination on the quality and inhibition of L. monocytogenes growth in ready-to-eat (RTE) smoked catfish fillets. Catfish fillets were tumbled with PL and PA, and treated with no smoke (NS), wood smoke (WS), liquid smoke 1 (LS1), and liquid smoke 2 (LS2). Wood smoke with antimicrobials (WSWA) showed greater inhibition (p < 0.05) of L. monocytogenes growth than other treatments with the exception of the LS1 treatment with antimicrobials. Consumers preferred (p < 0.05) smoked catfish fillets treated with WS to LS1 with respect to appearance, odor, flavor, texture, and overall acceptability. In conclusion, the use of PL and PA did not have a negative impact on the quality and sensory properties of smoked catfish fillets but had a synergistic effect with wood smoke constituents that inhibited the growth of L. monocytogenes.     

Textural and Sensory Properties of Herring (Clupea harengus) Cubes in Chinese-Type Paste as Affected by Prefrying Methods

The aim of this study was to determine the textural and sensory properties of herring (Clupea harengus) cubes prefried by deep frying (DF), mild frying (MF), and vacuum frying (VF) in Chinese-type pastes stored for 25 days at 13–15°C. Three groups of fish cubes in every Chinese-type paste were compared for texture, physical, and sensory properties by carrying out texture profile analysis (TPA), moisture content, color, and sensory analyses; and two types of Chinese-type pastes were investigated, oily Paste (A) and light Paste (B). The results showed that L* of fish cubes decreased significantly (p < 0.05), and a* and b* increased significantly (p < 0.05) in two kinds of Chinese-type pastes. Fish cubes prefried by DF and MF had higher sensory scores in Chinese-type Paste A, while those prefried by DF and VF had higher sensory scores in Chinese-type Paste B.     

Effect of Bacterial Community and Free Amino Acids on the Content of Biogenic Amines During Fermentation of Yu-lu,a Chinese Fermented Fish Sauce

The main objective of this work was to investigate the effects of bacterial community and free amino acids on the content of biogenic amines in Yu-lu during fermentation. Four major biogenic amines (histamine, tyramine, cadaverine, and putrescine) were identified, and the content of tyramine was positively correlated with histamine (R value = 0.9113). Aspartic acid, glutamic acid, histidine, leucine, and lysine were the dominant free amino acids. 16S rRNA sequencing showed that the composition of the bacterial community changed significantly during fermentation of Yu-lu. Principal component analysis revealed the crucial links between microbial community and biogenic amines. For example, Halanaerobium was probably associated with the formation of putrescine, while Halomonas might be associated with the degradation of biogenic amines at the end of fermentation of Yu-lu. This study provided a detailed evaluation of the Yu-lu fermentation process, enabling development of better strategies for biogenic amine control in fish sauce.     

Preparation of Extruded Snacks with Flavored Flour Obtained from the Carcasses of Nile Tilapia: Physicochemical,Sensory, and Microbiological Analysis

This study aimed to develop extruded snacks including flour obtained from Nile tilápia carcasses, and then evaluate the chemical composition, colorimetry, thiobarbituric acid reactive substances, and microbiology. There was a significant increase in the levels of crude protein, ether extract, ash, and minerals, as well as a reduction in carbohydrates as more flour was included in the snacks. Increased levels of flavored flour caused reduction in the brightness of snacks. Oxidative rancidity was not detected in snacks. The inclusion of flour improved the nutritional value of extruded snacks without changing sensory characteristics. Microbiologically, the snacks are suitable for human consumption.     

The Effects of Chitosan Coating on Biogenic Amines Inhibition and Microbial Succession of Refrigerated Grass Carp (Ctenopharyngodon idellus) Fillets

Chitosan coating and plastic wrap coating were investigated for their effects on the quality of grass carp fillets stored at 4 ± 1ºC for a period of 20 days. The fillets were divided into groups of untreated (Control), wrapped with sterile preservative film (PE), and chitosan-treated (1, 2, and 2.5% w/v corresponding to CH1, CH2, and CH2.5, respectively). The final result demonstrated that chitosan coating has positive effects on the microbial inhibition of total volatile count (TVC), lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas, H₂S-producing bacteria (including Shewanella putrefaciens), and Staphylococcus. With regard to the results of biogenic amines (BAs), putrescine (PUT) and histamine (HIS) were the major amines, and their concentration was significantly (p < 0.05) higher in Control and PE than in chitosan-coated fillets at the end of storage. The final concentration in Control, PE, CH1, CH2, and CH2.5 was 143.7, 160.1, 83.0, 59.4, and 44.2 mg/kg for PUT and 228.0, 57.1, 4.1 3.2, and 2.9 for HIS, respectively. Chitosan coating was found to inhibit the increase of total volatile base nitrogen (TVB-N), microbial population, and total BAs and prolong the shelf life of grass carp fillets. However, sterile plastic wrap coating had little positive effect on maintaining the quality of grass carp fillets during refrigerated storage.     

The Impact of Diets Supplemented with Different Forms of Rosemary and BHA on Chemical,Microbial and Sensory Properties of Rainbow Trout Fillet

The objective of this study was to evaluate the effect of different forms and doses of rosemary on chemical, microbial, and sensory properties of rainbow trout fed nine different diets: control (C), 20 g.kg^?1 rosemary powder (20RP), 40 g.kg^?1 rosemary powder (40RP), 0.3 g.kg^?1 rosemary extract (0.3RE), 0.6 g.kg^?1 rosemary extract (0.6RE), 0.15 g.kg^?1 rosemary nanopowder (0.15RNP), 0.3 g.kg^?1 rosemary nanopowder (0.3RNP), 0.15 g.kg^?1 butylated hydroxyanisole (BHA) (0.15BHA), and 0.3 g.kg^?1 BHA (0.3BHA). After 8 weeks’ feeding, the fish fillets were sampled on the 1st, 4th, 8th, 12th, and 16th days and then stored on 4°C. Lower value of pH, peroxide value (PV), total volatile base nitrogen (TVB-N), free fatty acids (FFA), and thiobarbituric acid (TBA) were reported in fish fed with RP, RE, RNP, and BHA; among them, RNP groups had the lowest properties (p < 0.05). Furthermore, lower total viable aerobic bacterial counts (TVC) and psychotropic counts (PTC) were observed in the fillets of the fish fed with rosemary treatments, especially in RNP treatments (7.52–9.41 log₁₀ CFU.g^?1), along with a slower spoilage in terms of sensory factors (texture, color, odor, and overall) on the 16th day. Finally, use of natural antioxidant nanorosemary in the diet may positively affect fish fillet quality and delay post-mortem deterioration.     

海洋酸化对水生动物骨骼和耳石钙化、生长发育的影响与机理

正自18世纪以来,大气中的pCO2增加了大约36%,大气中1/3以上的CO2为海水吸收,形成了大量的碳酸氢根(HCO-3)离子,使海洋表面的pH下降,形成不断加剧的海洋酸化现象[1],若不能有效控制CO2排放,到21世纪末,海洋表面的pH将下降0.3~0.4个单位,使表层海水pH达到80万年以来的最低值[2],影响海洋的生态环境和海洋生     

组胺对黄颡鱼生长及体色变异的影响

试验在基础饲料中分别添加0、10、100、1 000 mg/kg的组胺,制成4种等氮饲料(分别记为C、H10、H100和H1000),以黄颡鱼(Pelteobagrus fulvidraco)(102.13±0.52)g为试验对象,进行56 d的养殖试验,研究不同添加水平组胺对黄颡鱼生长、皮肤显微结构、皮肤黑色素含量、酪氨酸酶活力和脑中黑素皮质素受体-1(MC1R)mRNA表达量的影响。试验采用微流水室内养殖系统,结果表明:饲料中添加不同量组胺对黄颡鱼生长(增重率和特定生长率)无显著影响(P0.05),而高组胺添加量组(H1000组,组胺含量1 390 mg/kg)黄颡鱼皮肤中黑色素含量及脑组织中MC1R mRNA表达量显著低于对照组(P0.05),低添加量组(H10和H100)黄颡鱼皮肤黑色素含量和脑中MC1R mRNA表达量与对照组无差异(P0.05)。随着饲料中组胺添加量的增加,皮肤酪氨酸酶活力呈下降趋势,但各组间差异不显著(P0.05)。结果表明:组胺对黄颡鱼生长表现无影响,但会引起黄颡鱼体色白化,且白化程度与饲料中组胺含量密切相关。     

海水酸化对水生动物主要抗氧化酶的影响及机理

正海水吸收空气中的二氧化碳形成碳酸增加了海水的酸度,这种现象被称为海水酸化。据估测,到2100年,海水pH平均值将因此下降约0.3~0.4,至7.8~7.9[1]。海水pH值是海洋生态系统的关键因子,即使细微变化都将对海洋化学产生深刻影响[2],从而影响大多数海洋生物的生理、生化、代谢、生长、繁殖与生存,最终可能会导致海洋生态系统发生不可逆的变化,进而影响人类。海洋酸化     

水体中组织胺对黑褐新糠虾生长与发育的影响

研究了不同浓度组织胺(1 mg/L、3 mg/L和5 mg/L)养殖水体对黑褐新糠虾生长与发育的影响,其中0 mg/L为对照组。结果表明:水体组织胺对黑褐新糠虾生长和存活有显著影响。其中高浓度组(5 mg/L)黑褐新糠虾存活率仅为(83±12.47)%,而对照组为(97±4.71)%,两者存在显著差异(P<0.05)。组织胺对黑褐新糠虾的生长有显著抑制作用,用药17 d后,对照组体长为6.18±0.30 mm,而最高组织胺浓度组(5mg/L)的体长仅约为对照组的87%,即5.35±0.26 mm,两组间有显著性差异(P<0.05);抱卵雌虾的体长各组基本一致,均约为7.58±0.24 mm;组织胺能抑制黑褐新糠虾蜕壳,表现为同一时期内蜕壳比例较低;组织胺能延迟雄性黑褐新糠虾第二性征出现和雌性黑褐新糠虾抱卵的时间,分别延迟约1 d和3 d。     

Effect of Salt Concentration and Extremely Halophilic Archaea on the Safety and Quality Characteristics of Traditional Salted Anchovies

Extremely halophilic archaea (EHA) might play an important role in salted fish production. So far, limited information has been available on the effect of EHA and salt concentration on the safety and quality characteristics of salted anchovies. Eight Halobacterium salinarum strains were isolated from different sea salt samples and subjected to phenotypic and genotypic characterization. The strains were then inoculated into fresh salt before addition to anchovies. A total of 18 experimental productions were performed. The inoculated trials showed the lowest counts of undesired microorganisms. In particular, salted anchovies produced with Hbt. salinarum H11 showed the lowest histamine concentration as well as the highest sensory scores. Differences in terms of volatile organic compounds (VOCs) were estimated among trials. Furthermore, multivariate analysis showed that experimental production performed with a reduced amount of salt (175 g of sea salt per kg of anchovies) did not affect the final quality of salted anchovies. The strain Hbt. salinarum H11 produced salted anchovies with well-appreciated organoleptic features. Thus, the addition of EHA and the use of a lower amount of sea salt might represent a valuable alternative to the traditional method for production of salted anchovies.     

Processing and Digestion of Press Juices from Different Fish Muscles; Temperature and Lyophilization Effects on Their Anti-Oxidative Properties

Press juices (PJs) from seven, mostly underutilized, fish were tested for their anti-oxidative properties. The effects of thermal processing, freezing, and lyophilization of fresh PJs on these properties were investigated. Lyophilized samples were further subjected to in vitro digestion. It was concluded that thermal processing significantly affected only the ferric ions reducing ability, while freezing affected the anti-oxidative properties of only certain species. Lyophilized samples from Dactylopterus volitans and Trachinus draco were able to delay significantly the onset of hemoglobin-mediated oxidation. Finally, the exposure of the PJs to different pH values during in vitro digestion seemed to play an important role in their 1,1-diphenyl-2-picrylhydrazyl (DPPH)% inhibition ability.     

Effect of Fish Gelatin Coating Enriched with Oregano Essential Oil on the Quality of Refrigerated Rainbow Trout Fillet

ABSTRACT

In the present study, the effect of fish gelatin coating (FG; 4%, w/v) containing oregano (Origanum vulgare L.) essential oil (OEO; 1.2% w/v) on shelf-life extension of rainbow trout (Oncorhynchus mykiss) fillet stored under refrigerated storage (4 ± 1ºC) was investigated. The control and the treated fish samples were analyzed periodically for chemical (pH; total volatile basic nitrogen, TVB-N; peroxide value, PV; thiobarbituric acid, TBA) and microbiological (total viable count, TVC; psychrotrophic count) characteristics. The FG + OEO treatment produced significantly lower (p < 0.05) TVB-N values as compared to control and FG-coated samples after Day 6 and until the end of the storage period. The TBA values remained low and were found to fluctuate during storage. Results showed that TVC exceeded 6 log CFU g^?1 on Day 8 of storage for control and FG-coated samples and Day 12 for samples coated with FG + OEO. The reduction of 1.05 and 0.83 log CFU g^?1 of psychrotrophic counts was achieved by FG + OEO coating in trout fillet (p < 0.05) as compared with control and FG-coated samples, respectively. Therefore, the incorporation of OEO into FG coating may be a promising method of maintaining the storage quality of the rainbow trout fillet stored at refrigerated temperature.     

Effect of Liquid Smoke Dipping and Packaging Method on the Keeping Quality of Raw and Cooked Chub Mackerel (Scomber japonicus) Fillets

Changes in biochemical and sensory attributes of chub mackerel (Scomber japonicus) fillets during storage treated by immersion in a 12% NaCl brine with or without 0.2% liquid smoke were investigated. Brine-treated chub mackerel fillets were packaged in modified atmosphere or under vacuum and were stored at 4°C. The brined fillets were stored and evaluated raw and after heat treatment as cooked samples. Fish fillets were assessed organoleptically to determine acceptability and by measuring the pH, oxidation levels (TBARS test), and total volatile basic nitrogen (TVBN). Fillets treated in brine with liquid smoke exhibited similar pH and significantly lower TBARS and TVBN values (p < 0.05). The combination of the use of brines containing liquid smoke and subsequent vacuum packaging produced the lowest TBARS and TVBN values and resulted in extended acceptability.     

CO_2气调保鲜对鱼体pH值及细菌总数的影响

<正> 鲜鱼腐败是鱼体内酶和微生物共同作用的结果,前者将受一定条件的限制,后者则是自始至终起着作用。由于鲜鱼含水量高,组织脆弱,鱼肉天然免疫素少,鱼死后又迅速处于碱性反应等,故有利于腐败菌的生长。当前用于生产上鱼类保鲜的方法有多种,CO_2气调保鲜是其中之一,此法最大特点是能保持鱼品的原来风味。气调保鲜国外早在20世纪30年代就开始研究,近几十年来得到迅速发展并应用于渔业上,效果甚     

混合植物蛋白替代鱼粉对杂交鲟幼鱼生长、排氨率和转氨酶活性的影响

试验研究了豆粕、菜粕和棉粕组成的混合植物蛋白替代饲料中鱼粉,对杂交鲟幼鱼的生长、排氨率及转氨酶活性的影响。共设计了5种等氮、等能的饲料,分别用混合植物蛋白替代饲料中0%、25%、50%、75%和100%的鱼粉。养殖周期为84d,幼鱼平均体质量(8.63±0.23)g,流水养殖,水流速为0.2m/s,水温18~20℃。结果显示,100%试验组终末均质量、质量增加率和特定生长率显著低于对照组(P0.05),而存活率显著低于其他各组(P0.05)。25%和50%试验组排氨率较低,均显著低于其他各组(P0.05)。75%和100%试验组谷丙转氨酶和谷草转氨酶活性无显著差异(P0.05),但均显著低于其他各组(P0.05)。建议混合植物蛋白替代杂交鲟幼鱼饲料中鱼粉的比例不高于50%。