Chemical and microbiological changes of salted Caspian kutum (Rutilus frisii kutum) roe

Salted kutum roe was prepared by soaking in brine to a traditional procedure. Proximate composition (moisture, protein, lipid, pH, ash and salt content), total volatile basic nitrogen (TVB-N), fatty acid profiles and microbiological characteristics of raw and salted roe of Caspian white fish (Rutilus frisii kutum) were determined. The results indicated that protein and moisture contents were significantly higher in raw roe compared to salted one (28.81 and 61.07% to 23.99 and 51.57%, respectively). Significant differences in ash and salt contents were obtained among different treatments. TVB-N in all samples was less than 25mg/100g. The gas chromatography (GC) analysis showed that the major saturated fatty, monounsaturated fatty acids and poly unsaturated fatty acids were 16:0, 18:1n-9, and 22:6n-3, respectively. Aerobic plate count (APC) and Total Coliform Count (TC) in all samples were significantly higher (p<0.05) in raw roe (5.33 logCFU/g and 210 MPN/g) compared to salted roe (1.23 log CFU/g and 1.2 MPN/g). None of the samples contained Escherichia coli, Salmonella, Clostridium perfringens or yeast

Inhibitory effect of citric acid on rancidity of frozen catfish (Silurus glanis)fillets

The effect of aqueous solution of citric acid (CA) on the lipid stability of the European catfish (Silurus glanis) fillets during frozen storage (up to 6 months) was investigated. Rancidity development was measured by several biochemical indices (free fatty acids, peroxides and TBA) and complemented by the measurement of expressible moisture and sensory evaluation (flesh odor, consistency and flesh appearance). The CA treatment led to some lower free fatty acids (6.43% oleic acid in total lipid at month 6), peroxides (7.98meq oxygen/kg lipids, at month 6) and secondary compounds formation (2.16mg malondialdehyde/kg fish sample). Lower peroxide, thiobarbituric acid-reactive substance (TBA), free fatty acids (during 0,3 and 6 months frozen storage), and expressible moisture (month 6) values were obtained from CA-treated fish fillets than the untreated (blank control) ones (P<0.05)

Inhibition of fatty acids profile changes of cobia (Rachycentron canadum) fillets during frozen storage by packaging under vacuum system

This study was aimed to investigate the effect of vacuum packing (VP) on the fatty acids profiles in cobia (Rachycentron canadum) fillets during an extended frozen storage period. Cobia fillets were treated under vacuum system then stored at -18°C for up to 6 months and compared to control conditions. As a result of a frozen storage period of 6 months, a marked content decrease was found in the fatty acid groups such as MUFA, PUFA and ω-3 PUFA, as well as in the ω-3/ ω-6 ratio. However, a preserving effect on such fatty acid parameters could be observed due to the VP treatment. Assessment of the polyene index (PI) indicated an increased lipid oxidation development as a result of the frozen storage time; however, this increase was partially inhibited by the vacuum packaging. Results indicate that vacuum packaging was a proper way to reduce lipid oxidation in Cobia fillets and extend their shelf life by omitting available oxygen. Thus the employment of VP alone or in combination with other protective strategies is recommended

Effect of oregano and thyme essential oils on the microbiological and chemical quality of refrigerated (4ºC) ready-to-eat squid rings

9 páginas, 4 tablaThe efficacy of oregano and thyme essential oils (OEO and TEO, respectively) in the quality retention of a refrigerated (4 °C) squid (Loligo vulgaris) ring ready-to-eat (RTE) product was studied. Essential oils were added at different concentrations to the coating medium during processing. An inhibitory (P 0.05) of the OEO concentrations on lipid oxidation development was detected. The addition of TEO did not lead to an inhibitory effect (P > 0.05) on the microbial activity of the refrigerated RTE squid, although a slight inhibitory (P < 0.05) effect on lipid oxidation was observed in the batches including the higher TEO concentrations.Peer reviewe

Optimization of encapsulation of fish protein hydrolysate and fish oil in W1/O/W2 double emulsion: Evaluation of sensory quality of fortified yogurt

In this study, water-in-oil-in-water (W1/O/W2) double emulsions were prepared in which fish protein hydrolysate as W1 phase and fish oil as O phase were used within a complex of whey protein concentrate (WPC) and inulin. The double emulsions were optimized in terms of the release, creaming index, encapsulation efficiency, and encapsulation stability using the response surface methodology. The coefficients of determination were higher than 0.880 for all the response variables and the independent variables had significant effects on all responses. The optimum levels of the independent variables were as follows: 2:1 w/w ratio of wall/core, 2.12:1 w/w ratio of WPC/Inulin, and 6.28 polyglycerol polyricinoleate. For the sensory analysis, natural yogurt was fortified with microcapsules obtained from a freeze-dried W1/O/W2 emulsion with an optimized formulation. The visual appearance of the yogurt was not affected by the microcapsules and addition of a flavoring agent for masking fish oil flavor was recommended. Practical applications: Thermodynamic instability of double emulsion let to investigate different production condition in order to produce stable emulsion. In this case, response surface methodology has been broadly used to optimize the conditions of different procedures. In this study, optimization of wall/core weight ratio, WPC/inulin weight ratio and emulsifier concentration was developed to achieve minimum amounts of the release and creaming index and maximum amounts of the encapsulation efficiency and encapsulation stability. At the second step, yogurt were fortified by optimized microcapsules and the sensory analysis did not show significant differences in rancid and bitter taste during eating between the control and the fortified sample. © 2019 Wiley Periodicals, Inc

Impact of wall materials on physicochemical properties of microencapsulated fish oil by spray drying

12 páginas, 5 tablas, 1 figuraThe aim of the present study was to investigate the effect of wall materials composition on physicochemical char- acteristics of fish oil microcapsules produced by spray drying (180 °C). Four different combination of coating materials (fish gelatin, chitosan, combination of gelatin and chitosan, and a mixture of microbial transglutaminase (MTGase) with malto- dextrin) were applied to two different fish oils to produce 40 % solid emulsions. Scanning electron microscopy and extraction of surface and encapsulated oils revealed that fish gelatin provided the highest preserving effect on the covering fish oil. Meantime, addition of MTGase to gelatin could also increase this ability and reveled less surface oil than chitosan treatment (2.63 and 2.80 % versus 4.66 and 5.23 %, respec- tively; P <0.05). Mixture of gelatin and maltodextrin with MTGase as wall material led to the highest encapsulation efficiency, being selected as the best microencapsulation con- dition; meantime, application of chitosan with maltodextrin provided the worse encapsulation efficiency ( P <0.05). All indices of powders (encapsulation efficiency, surface mor- phology, and particle size) showed that powders prepared from gelatin and gelatin with MTGase increased the encapsu- lation efficiency and would increase the stability of microcap- sule powdersPeer reviewe

Using WPC-inulin-fucoidan complexes for encapsulation of fish protein hydrolysate and fish oil in W1/O/W2 emulsion: Characterization and nutritional quality

The double emulsions and freeze-dried microcapsules containing fish protein hydrolysate (FPH) and fish oil (FO) were stabilized by complexs of whey protein concentrate (WPC) with inulin (Inu) and fucoidan (Fuc) in terms of physical characteristics (particle size distribution, morphology, encapsulation efficiency, solubility, …), oxidative stability, nutritional quality and in vitro release. Higher encapsulation efficiency and solubility were observed in Fuc-WPC microcapsules (86.31 and 30.26 mg/100 g, respectively). The combination of Fuc-WPC in the wall material showed higher oxidative stability than other wall material. The higher values of PUFA and SFA were observed in Inu-WPC Fuc-WPC microcapsules, respectively. The Fuc-WPC and Inu + Fuc-WPC micrographs showed a more porous structure compared to Inu-WPC. The mean particle size ranged from 536.8 ± 52.70 to 842.36 ± 21.41 nm. No significant differences were observed in the released oil and the fatty acid composition during gastrointestinal digestion. Sensory evaluation of fortified natural yogurt with microcapsules showed lower fishy flavor in Inu-WPC samples than those fortified with Fuc-WPC and Inu + Fuc-WPC. In general, the use of inulin with WPC as a wall materal resulted in good characteristics and sensory attributed, although the use of fucoidan with WPC conferred higher oxidative stability during storage. © 2018 Elsevier Lt

An investigation of rancidity inhibition during frozen storage of Wels catfish (Silurus glanis) fillets by previous ascorbic and citric acid treatment

7 páginas, 3 figuras, 3 tablasThe effect of preliminary ascorbic and citric acid (AA and CA, respectively) soaking treatments on the rancidity development in Wels catfish (Silurus glanis) fillets during further frozen storage (−18 °C; up to 6 months) was studied. Rancidity development was measured by biochemical quality indices (formation of free fatty acids, peroxides and secondary oxidation products) and compared with sensory analysis (appearance, rancid odour and consistency) and general chemical analyses (pH, expressible moisture and heme iron contents). When compared with control samples, AA- and CA-treated samples showed a lower (P < 0.05) formation of primary and secondary lipid oxidation compounds that was corroborated by a longer (P < 0.05) shelf-life time as a result of a lower rancid odour formation. According to these results, control samples showed a higher (P < 0.05) heme iron breakdown (months 3–6) and a lower (P < 0.05) water-holding capacity (higher expressible moisture value) (month 6)Peer reviewe

Effect of different concentrations of pure and mixed salt on the shelf life of salted rainbow trout (Oncorhynchus mykiss) roe during refrigerated storage

This study aimed to investigate the effects of salting of rainbow trout (Onchorhynchus mykiss) roe by pure and mixed salts (3.5, 4.5 and 5.5 %) on the quality and shelf life of the product, with respect to the contents of Total Volatile base nitrogen (TVBN), lipid oxidation (TBA), and on the proximate compositions during storage. The processing of roe leaded to changes in its chemical composition. In comparison with fresh roe, salted roe presented higher contents of TBA and lower content of TVBN. The greatest increases of TVBN were observed in the samples salted by salt without additives, in which TVBN was detected at 43.43 mg/100 g. pH value, salt absorption and TVBN and lipid oxidation had significant increase during storage (