Lipid damage inhibition by previous high pressure processing in white muscle of frozen horse mackerel

Effect of Rigor Stage and Pressurisation on Lipid Damage, Total Volatile Amine Formation and Autolysis Development in Palm Ruff Stored on Ice

The effect of the rigor stage (pre or post) and previous high-pressure processing (HPP; 450 and 550 MPa for 3 min) was checked during the storage on ice of farmed palm ruff (Seriolella violacea). Fish processed in pre-rigor conditions led to higher and lower levels (p < 0.05) of moisture and lipid contents in chilled fish, respectively, when compared to their counterpart samples processed in the post-rigor stage. Pre-rigor fish showed a higher (p < 0.05) quality level than post-rigor samples according to the assessment of the K value (59.0-92.1 and 70.3-96.3 ranges, respectively), fluorescent compounds (0.29-1.11 and 0.37-1.90 ranges, respectively), free fatty acids (FFA) (15.1-188.0 and 33.8-232.5 g·kg^-1 lipids ranges, respectively), and total volatile amines (216.3-387.6 and 217.7-412.2 g·kg^-1 muscle ranges, respectively). Pressure-treated fish showed higher (p < 0.05) quality retention than non-treated samples according to the formation of fluorescent compounds (0.29-0.86 and 0.85-1.90 ranges, respectively), FFA (15.1-50.6 and 58.9-223.5 g·kg^-1 lipids ranges, respectively), and total volatile amines (216.3-250.3 and 351.1-412.2 g·kg^-1 muscle ranges, respectively) and the evolution of the K value (59.0-77.2 and 86.9-96.3 ranges, respectively). The use of pre-rigor fish and previous HPP is recommended for the commercialisation of the current species as a fresh product.

Antioxidant Effect of Octopus Byproducts in Canned Horse Mackerel (Trachurus trachurus) Previously Subjected to Different Frozen Storage Times

The effects on lipid damage in canned horse mackerel (Trachurus trachurus) of a prior frozen storage (−18 °C) period and the presence of an octopus (Octopus vulgaris) cooking juice (OCJ) in the packing medium were investigated. An increase of the frozen storage time favoured an increase (p < 0.05) of free fatty acid (FFA), peroxide, and thiobarbituric acid reactive substance contents and a decrease (p < 0.05) of the phospholipid (PL) value and polyene index. Furthermore, an increased presence of OCJ in the packing medium led to an inhibitory effect (p < 0.05) on fluorescent compound formation as well as to a retention (p < 0.05) of the PL and FFA compounds. Colour determination showed a substantial increase (p < 0.05) of L* and b* values in canned fish with previous frozen storage time. Nevertheless, this increase was partly reduced (p < 0.05) by the OCJ presence in the packing medium. It is concluded that previous holding time has led to an increased lipid oxidation development and loss of beneficial lipid constituents (i.e., PLs and polyunsaturated fatty acids). Remarkably, the presence in the packing medium of preservative compounds (i.e., antioxidants) included in waste juice obtained from octopus processing provided an effective tool for lipid preservation and quality enhancement in canned fish.

Effects of Ozone Water Combined With Ultra-High Pressure on Quality and Microorganism of Catfish Fillets (Lctalurus punctatus) During Refrigeration

This study described the quality and microbial influence on ozone water (OW) and ultra-high pressure (UHP) processing alone or in combination with refrigerated catfish fillets. The analysis parameters included total volatile base nitrogen (TVBN), thiobarbituric acid reactive substances (TBARs), chromaticity, microbial enumeration, 16S rRNA gene sequencing, electronic nose (E-nose), and sensory score. The study found that compared with the control (CK), ozone water combined with ultra-high pressure (OCU) delayed the accumulation of TVBN and TBARs. The results of sensory evaluation illustrated that OCU obtained a satisfactory overall sensory acceptability. The counting results suggested that compared to CK, OCU significantly (p < 0.05) delayed the stack of TVC, Enterobacteriaceae, Pseudomonas, lactic acid bacteria (LAB), and hydrogen sulfide-producing bacteria (HSPB) during the storage of catfish fillets. The sequencing results reflected that the dominant were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria at the phylum level, and the dominant were Acinetobacter, Pseudomonas, Lelliottia, Serratia, Shewanella, Yersinia, and Aeromonas at the genus level. The dominant was Acinetobacter in initial storage, while Pseudomonas and Shewanella were in anaphase storage. Based on the TVC and TVBN, the shelf life of catfish fillets was extended by at least 3 days compared to the control. In short, the combination of ozone water and ultra-high-pressure processing is a favorable strategy to control microbial quality and delay lipid oxidation during catfish storage.

Comparative effect of a previous 150-MPa treatment on the quality loss of frozen hake stored at different temperatures

BACKGROUND

This study addresses the quality loss of European hake (Merluccius merluccius) during frozen storage. Its objective was to comparatively analyse the effect of a previous high-pressure processing (HPP) (150 MPa for 2 min) when different storage temperatures (-10, -18 and -30 °C) were employed.

RESULTS

Most chemical quality indices (trimethylamine, TMA; dimethylamine, DMA, formaldehyde, FA; free fatty acids, FFAs) provided a marked content increase with freezing and frozen storage time, values being higher by increasing the storage temperature. Previous HPP led to an inhibitory (P < 0.05) effect on the TMA, DMA, FA and FFA formation in frozen fish kept at -10 and -18 °C, the preservative effect being higher at the highest temperature tested; however, in agreement to the low damage development, no effect could be proved on samples stored at -30 °C. Concerning lipid oxidation, peroxides formation was found low, although a slight increasing effect (P < 0.05) was implied in fish corresponding to all temperatures as a result of the previous HPP; furthermore, an inhibitory effect (P < 0.05) on fluorescent compounds formation (tertiary lipid oxidation) was evident after freezing and at month 9 for -10 °C samples.

CONCLUSION

It is concluded that a 150-MPa high-pressure treatment may inhibit the formation of degradative molecules such as DMA, FA, TMA and FFAs during the frozen storage at -18 °C (maximum recommended) and -10 °C. However, results have indicated that lowering the storage temperature showed to be more effective than the current HPP (150 MPa for 2 min). © 2020 Society of Chemical Industry.

Effect of high-pressure processing pretreatment on the physical properties and colour assessment of frozen European hake (Merluccius merluccius) during long term storage

Fish freshness is lost by autolytic degradation produced by endogenous enzymes. Frozen storage is one of the most used methods to preserve fish properties. However, protein denaturation has shown to be a major problem for frozen European hake (Merluccius merluccius), leading to texture losses and off-odour development. The aim of this work was to study the changes produced by high-pressure processing (HPP) before freezing on quality of frozen European hake stored at -21 °C for 12 months. The effect of HPP (150-450 MPa) on mechanical properties and expresible water was evaluated in raw and cooked fish samples. The effect on colour (L*, a* and b*) was assessed only in raw fish. Results showed that HPP before freezing is beneficial to maintain expresible water in good levels up to 6 months. The luminosity significantly increased with pressure level. Textural profile of raw samples showed that HPP increased hardness, adhesiveness and springiness of frozen hake. Cooked samples were also affected by HPP, being the best results obtained at 300 MPa for 6 months of frozen storage. Overall, results showed that HPP improves the quality of frozen hake.