Polyphenol Uses in Seafood Conservation

Effects of Annona muricata extraction on inhibition of polyphenoloxidase and microbiology quality of Macrobrachium rosenbergii

Giant freshwater prawn (Macrobrachium rosenbergii) is one of the important aquaculture species and quickly expanding in many countries. High demand and mass commercialization on M. rosenbergii regulating 18% of the international seafood business. Seafood products contend with various level across the supply chains and time to reach the consumers depending upon the marketing and delivery channels after harvesting. Therefore, these may cause biodeterioration such as melanosis (dark pigmentation) and microbial changes that limit the shelf life. This studies reveal the antioxidant properties from Annona muricata leaves extract and their effectiveness in inhibiting the polyphenoloxidase (PPO) activity and delaying the bacterial accumulation during 20 days of chilled storage. Five metabolites including coumarins, flavonoid, glycoside, terpenoids and steroid compound were found in A. muricata leaves extract. Total phenolic content and total flavonoid content of A. muricata were recorded at 191.24 ± 0.03 mgGAEg^-1 and 1777.48 ± 1.08 mgQEg^-1, respectively. Sixteen percent (16%) of A. muricata leaf extract effectively inhibit 82.41% PPO. Furthermore, 15% of A. muricata leaves extracts showed a significant reduced (p < 0.05) in total bacteria count during 20 days of chilled storage of M. rosenbergii. These conclude that the present of listed secondary metabolites and at approximately ~ 15-16% of A. muricata leaves extracts were effectively inhibiting the melanosis and prolong the shelf life for up to 8 days of M. rosenbergii stored at chilled condition. Therefore, A. muricata leaves extract is potential used as natural preservative agent in obtaining high quality seafood products.

The combined impact of cold smoking and natural antioxidants on quality and shelf life of dolphinfish (Coryphaena hippurus) fillets

This study aimed to produce new value-added products from dolphinfish (Coryphaena hippurus) as fillets when using cold smoking combined with natural antioxidants, obtained from Halocnemum strobilaceum a plant belonging to halophytes. The fillet treatments were controlled (untreated), immersed in standard brine (STD), treated with NaCI and antioxidant before freezing (Aox-pre) and treated with NaCl and antioxidant after thawing (Aox-post). The quality of dolphinfish fillets was assessed using sensory, biochemical, microbiological, and technological parameters. Treating fillets with antioxidants before freezing and cold smoking (Aox-pre) enhanced significantly the shelf life, as well as improved the biochemical, microbiological, and sensory aspects of the product. Aox-pre fillets had the lowest peroxide values (PV) and malondialdehyde (MDA) content, demonstrating that the immediate treatment of fillets with the polyphenols protected lipids from peroxidation. The smoking process, together with antioxidant treatment, significantly reduced microbial counts after 15 days of storage, compared to the control. Overall, combining antioxidant treatments with cold smoking has a positive effect on the quality of Aox-pre fillets with respect to both sensory components and biochemical parameters associated with shelf life. Consequently, Aox-pre treatment enhances the marketability of this species, promoting local and seasonal products, contributing to costal fisheries sustainability.

A Critical Review of the Characterization of Polyphenol-Protein Interactions and of Their Potential Use for Improving Food Quality

BACKGROUND

Interest in protein-phenol interactions in biological systems has grown substantially in recent decades.

METHODS

The interest has focused largely on food systems in response to reports on the prominent roles of phenolic compounds in nutrition and health.

RESULTS

Phenolic compounds can have both favourable and adverse nutritional effects. Polyphenols are widely known for their antioxidant, anti-inflammatory, anticancer and antiaging properties; however, they have also been ascribed anti-nutritional effects resulting from interactions with some proteins and enzymes. Interactions between proteins and polyphenols can additionally influence food quality by altering some physical-chemical and sensory properties of foods. These effects may be useful to develop new products in food science and technology provided the nature of physical-chemical interactions between proteins and phenols is accurately elucidated. In this paper, we review the different possible modes of interaction between selected food proteins and phenolic compounds.

CONCLUSION

Existing knowledge on the mechanisms behind polyphenol-protein reactions, the structures of the resulting products and their potential uses is reviewed.

Retardation of lipid oxidation using gelatin film incorporated with longan seed extract compared with BHT

The aim of the present work was to apply the gelatin films with different levels of longan seed extract (LS) or butylated hydroxytoluene (BHT) on retardation of lipid oxidation in soybean oil. The films incorporated with various concentrations of aqueous LS (0, 50, 100, 300, and 500 ppm) or BHT (50, and 100 ppm) were developed. The films had transmittance percentages of 60-80 % at 570 nm and showed good light barrier properties when the concentration of LS or BHT increased. About 97 % protein solubility and 41 to 54 % water solubility were obtained for the developed films. Antioxidative activity of gelatin films incorporated with LS increased markedly with increasing storage time as indicated by the increase in DPPH radical scavenging activity (41-50 %) (P < 0.05). Films incorporated with LS or BHT showed the preventive effect on lipid oxidation of soybean oil during 30 days of storage. At the level of 500 ppm, LS provided the highest efficacy for lipid oxidation retardation as evidenced by lower conjugated diene (CD) values (P > 0.05). According to these findings, gelatin film incorporated with longan seed extract or BHT could be used as a tool to prolong the shelf-life of oily foods.