Persea Americana Mill seed extracts: Understanding insights into the antioxidant and antityrosinase activities and effects on preserving qualities of whiteleg shrimp (Litopenaus vannamei) during refrigerated storage

Exploring the Therapeutic Potential of Camellia longii Orel & Luu Leaf Extracts for Memory Loss in Alzheimer's Disease: Novel Findings and Functional Food Applications

Novel research on the chemical compositions and biochemical activities of Camellia longii Orel and Luu leaf extracts revealed valuable resources with potential applications in Alzheimer's disease treatment. Qualitative phytochemicals detected various compound groups, including polyphenols, saponins, tannins, flavonoids, alkaloids, amino acids, coumarins, and polysaccharides. HPLC-MS identified 23 compounds in C. longii leaves with compounds found at significant levels, including epicatechin gallate (17.12%), tryptophan (13.73%), isovitexin (12.91%), gallic acid (3.06%), and quercetin (3.06%). Interestingly, the ethanol extract (CLL-Ew) exhibited the highest extraction yield (26.6%) and potent antioxidant and acetylcholinesterase (AChE) inhibitory effects in vitro. In the Drosophila melanogaster model, CLL-Ew improved longevity, movement, and memory by reducing malondialdehyde and increasing glutathione levels. Docking simulations suggested that the above compounds bind tightly to AChE's active site, potentially contributing to memory enhancement. Interestingly, observations of male and female mice after administration of a dose of 5000 mg/kg C. longii leaf extract were recorded normally throughout the 14 day experiment. These findings highlight the potential of C. longii leaf extracts in functional foods and therapeutic interventions for memory impairment prevention and treatment.

Expression of polyphenol oxidase of Litopenaeus vannamei and its characterization

Polyphenol oxidase (PPO) plays a critical role in decrement of shrimp quality. To obtain active PPO and elucidate its enzymatic properties, PPO from Litopenaeus vannamei (Lv-PPO) was cloned, expressed in E. coli and purified by affinity column chromatography. The Lv-PPO gene was 2076 bp in length encoding 691 amino acids. The recombinant Lv-PPO (rLv-PPO) with a molecular mass of ∼85.0 kDa was successfully expressed and its sequence was verified by LC-MS/MS. rLv-PPO was biologically active with an optimal temperature of 40℃ and an optimal pH of 6.0. Metal ions Cu2+ and Zn2+ altered the activity of rLv-PPO by influencing its secondary and tertiary structures. rLv-PPO showed catalytic activity towards l-Dopa and catechol. A specific polyclonal antibody against rLv-PPO was prepared. Western blot analysis revealed that PPO levels were highest in hemolymph, followed by telson, carapace, and eyestalk. Expression of rLv-PPO will assist future studies on the mechanism in shrimp melanosis.

Polymeric Packaging Applications for Seafood Products: Packaging-Deterioration Relevance, Technology and Trends

Seafood is a highly economical product worldwide. Primary modes of deterioration include autolysis, oxidation of protein and lipids, formation of biogenic amines and melanosis, and microbial deterioration. These post-harvest losses can be properly handled if the appropriate packaging technology has been applied. Therefore, it is necessary for packaging deterioration relevance to be clearly understood. This review demonstrates recent polymeric packaging technology for seafood products. Relationship between packaging and quality deterioration, including microbial growth and chemical and biochemical reactions, are discussed. Recent technology and trends in the development of seafood packaging are demonstrated by recent research articles and patents. Development of functional polymers for active packaging is the largest area for seafood applications. Intelligent packaging, modified atmosphere packaging, thermal insulator cartons, as well as the method of removing a fishy aroma have been widely developed and patented to solve the specific and comprehensive quality issues in seafood products. Many active antioxidant and antimicrobial compounds have been found and successfully incorporated with polymers to preserve the quality and monitor the fish freshness. A thermal insulator has also been developed for seafood packaging to preserve its freshness and avoid deterioration by microbial growth and enzymatic activity. Moreover, the enhanced biodegradable tray is also innovative as a single or bulk fish container for marketing and distribution. Accordingly, this review shows emerging polymeric packaging technology for seafood products and the relevance between packaging and seafood qualities.

Cytotoxicity Evaluation and Antioxidant Activity of a Novel Drink Based on Roasted Avocado Seed Powder

The avocado seed is an underused waste resulting from the processing of pulp. Polyphenols, fibers, and carotenoids are present in the seed, which also exhibits prophylactic, fungicidal, and larvicidal effects. Developing food products with avocado seed as an ingredient or spice is highly desired for nutritional, environmental, and economic reasons. The present study proposed its valorization in a hot drink, similar to already existing coffee alternatives, obtained by infusing the roasted and grinded avocado seed. The proximate composition of the raw or conditioned avocado seed and that of the novel drink were determined. The total phenolic content was assessed using the Folin-Ciocâlteu method. The total carotenoids were extracted and assessed spectrophotometrically. Starch determination was performed by the Ewers Polarimetric method. The highest content of polyphenols, 772.90 mg GAE/100 g, was determined in the crude seed, while in the drink was as low as 17.55 mg GAE/100 g. However, the proposed drink demonstrated high antioxidant capacity, evaluated through the DPPH method. This might be due to the high content of the total carotenoid compounds determined in the roasted seed (6534.48 µg/100 g). The proposed drink demonstrated high antiproliferative activity on Hs27 and DLD-1 cell lines.

Calcined Oyster Shell Powder as a Natural Preservative for Maintaining Quality of White Shrimp (Litopenaeus vannamei)

Simple Summary

The Food and Agriculture Organization of the United Nations (FAO) indicated that the average global production of oyster shell waste for the year 2019 was 3.08 million tons. Many serious problems include the emission of displeasing odors and pollution of the seaside, which are harmful to the environment. Nonetheless, a solution for this issue would be to reuse the waste and produce a product that has economic benefits and solves the environmental problems. Using calcined oyster shells as a natural preservative might solve the problem of oyster shell waste. In this study, we used calcined oyster shell powder (COSP) as a natural preservative for improving shrimp shelf-life during 12 days under refrigerated conditions. As compared with the control, COSP treatment effectively retarded pH change, reduced the formation of total volatile basic nitrogen, and inhibited bacterial growth during refrigerated storage. The development of preservatives for aquatic products is expected to delay the growth of and spoilage by microorganisms in the refrigerated state, thus providing more barrier protection for aquatic food safety.

Abstract

Oyster shell waste has led to many problems, including displeasing odors, pollution of the seaside, and harm to the environment. Using calcined oyster shells as a natural preservative might solve the problem of oyster shell waste. We studied the use of calcined oyster shell powder (COSP) as a natural preservative for improving shrimp shelf-life over 12 days under refrigerated conditions. As compared with the control, COSP treatment effectively retarded pH change, reduced the formation of total volatile basic nitrogen, and inhibited bacterial growth during refrigerated storage. In addition, shrimp muscle lipid oxidation measured by peroxide value (PV) and thiobarbituric acid (TBA) was decreased during storage. The quality was preserved up to 12 days with 2.0–4.0% COSP treatment as compared with only 6 days for un-treated shrimp. The development of preservatives for aquatic products is expected to delay growth of and spoilage by microorganisms in the refrigerated state, thus providing more barrier protection for aquatic food safety.