Elsevier

LWT

Volume 123, April 2020, 109050
LWT

Prevention of protein and lipid oxidation in freeze-thawed bighead carp (Hypophthalmichthys nobilis) fillets using silver carp (Hypophthalmichthys molitrix) fin hydrolysates

https://doi.org/10.1016/j.lwt.2020.109050Get rights and content

Highlights

  • Fin hydrolysates (FH) prevented freeze-thaw-induced protein oxidation in fillets.

  • FH delayed lipid oxidation in freeze-thawed fillets.

  • FH could be potent antioxidants in fillet preservation.

Abstract

Conversion of aquatic by-products into value-added food ingredients has gained great interest worldwide, and enzymatic hydrolysis is one of the most accepted methods for the recovery of by-product proteins. In our study, fins from silver carp (Hypophthalmichthys molitrix) were hydrolyzed by four enzymes (trypsin, alcalase, papain, and neutrase) and the antioxidant activity of the derived fin hydrolysates was evaluated both in vitro and in freeze-thawed bighead carp (Hypophthalmichthys nobilis) fillets. The results showed that fin hydrolysates by trypsin and alcalase exhibited strong in vitro scavenging activity against 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and chelating activity to ferrous ions. Freeze-thaw-induced protein oxidation (the formation of carbonyls and disulfide bonds) and degradation (the loss of Ca2+-ATPase activity) were significantly (P < 0.05) inhibited by fin hydrolysates. In addition, fin hydrolysates reduced lipid oxidation as evidenced by decreased free fatty acid content, peroxide value, thiobarbituric acid reactive substances (TBARS), and fluorescent compounds after multiple freeze-thaw cycles. Therefore, fin hydrolysates by trypsin and alcalase could be potential natural antioxidants in preservation of fish fillets.

Introduction

Frozen storage is a widely accepted method for long-term quality/nutrient retention of aquatic products. Although microbial growth and enzyme activity are effectively terminated by low temperatures, the oxidation of protein and lipid still occur (Santos et al., 2019) and lead to deterioration in physicochemical properties, especially in conditions of temperature fluctuation and repeated freeze-thaw cycles (Nikoo, Benjakul, & Rahmanifarah, 2016). In order to alleviate discoloration, off-flavor, and other nutritional losses caused by lipid or protein oxidation, synthetic antioxidants, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) have been used. However, due to the concerns of toxicological effects of these synthetic antioxidants, exploration in natural plant- or animal-based antioxidants has aroused great interest (Falowo, Fayemi, & Muchenje, 2014).

To achieve a sustainable development in surimi processing industry, freshwater fish species like silver carp (Hypophthalmichthys molitrix) has been recognized as great alternatives (Martin-Sanchez, Navarro, Perez-Alvarez, & Kuri, 2009). During surimi manufacturing, tremendous quantity of by-products with low economic value and high-quality proteins, including scales, viscera, skin, bones, fins, etc. are generated and they require further recovery and utilization (Bruno, Anta Akouan Ekorong, Karkal, Cathrine, & Kudre, 2019). Compared with the traditional direct discarding or processing into fish meal or fertilizers, better valorization technology, for example, controlled enzymatic hydrolysis, is gradually appreciated for its value-added possibility (Jayathilakan, Sultana, Radhakrishna, & Bawa, 2012).

Native fish proteins can be hydrolyzed by enzymes into fish protein hydrolysates (FPH) that contained low molecular weight peptides with specific health-promoting bioactivities (Nikoo & Benjakul, 2015; Nikoo et al., 2016). A set of hydrolysates derived from fish by-products with in vitro antioxidant activity were discovered and showed promising potential as antioxidants in aquatic products (Atef & Ojagh, 2017; Chalamaiah, Kumar, Hemalatha, & Jyothirmayi, 2012; Zamora-Sillero, Gharsallaoui, & Prentice, 2018). As important parts of by-products, fins are rich in high-quality collagen (Mahboob, 2014; Nagai & Suzuki, 2000), however, the utilization of fin collagen through enzymatic hydrolysis is rarely investigated (Ahn, Kim, & Je, 2014). Hence, in our study, in vitro antioxidant activity of fin hydrolysates of silver carp by different enzymes (trypsin, alcalase, papain, and neutrase) was examined as well as its potential inhibitory effect on lipid and protein oxidation in freeze-thawed bighead carp (Hypophthalmichthys nobilis) fillets, which might provide a better waste-handling strategy for surimi processing industry.

Section snippets

Materials

Food grade alcalase from Bacillus licheniformis (280, 000 U/g) and papain from Carica papaya (240, 000 U/g) were purchased from Novozymes (Beijing, China), trypsin (200, 000 U/g) and neuturase (135, 000 U/g) were purchased from Sigma-Aldrich (Shanghai, China) and Angel Yeast Co., Ltd. (Wuhan, Hubei, China), respectively. Tea polyphenol (99.8%) was purchased from Wanbo Co., Ltd (Zhengzhou, Henan, China).

Preparation of fin hydrolysates

Silver carp (Hypophthalmichthys molitrix) (weight: 1947 ± 84 g, n = 20) were purchased from a

Antioxidant activity

Oxidative damages in meat and meat products are believed to be initiated by free radicals (Falowo et al., 2014). Fin hydrolysates by four enzymes showed similar tendency in scavenging activity toward ABTS radicals that characterized as sharp increases (P < 0.05) within 2 h of hydrolysis and then remained stable until 4 h (Fig. 1a). Compared with fin hydrolysates by papain and neutrase, enzymatic hydrolysis by trypsin and alcalase showed significantly (P < 0.05) higher quenching activity of ABTS

Conclusion

Fins from silver carp were hydrolyzed using four commercial enzymes (trypsin, alcalase, neutrase, and papain). Fin hydrolysates by trypsin and alcalase showed strong in vitro ABTS radical scavenging and Fe2+-chelating activities. After being added to fillets, both fin hydrolysates effectively reduced freeze-thaw-induced protein/lipid oxidation and degradation. Therefore, fin hydrolysates could be used as promising antioxidants in preservation of aquatic products, and the research into fin

CRediT authorship contribution statement

Longteng Zhang: Investigation, Validation, Writing - original draft, Formal analysis. Yuankai Shan: Investigation, Formal analysis. Hui Hong: Methodology, Software, Supervision. Yongkang Luo: Conceptualization, Supervision, Writing - review & editing. Xiaohui Hong: Writing - review & editing. Weijian Ye: Writing - review & editing, Supervision.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This study was supported by Open Project Program of Key Laboratory of Refrigeration and Conditioning Aquatic Processing, Ministry of Agricultural and Rural Affairs (KLRCAPP2018-05), Earmarked Fund for China Agriculture Research System (CARS-45), and Open Project Program of Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University.

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