Effect of Sodium Alginate in Combination with Zataria multiflora Boiss. on Phenolic Compounds, Antioxidant Activity, and Browning Enzymes of Fresh In-Hull Pistachio (Pistacia vera L.)

Maryam Hashemi,Ahmad Shakerardekani,SeyedHossein Mirdehghan,Abdolmajid Mirzaalian Dastjerdi,Barbara Speranza

doi:10.1155/2021/3193573

Abstract

The color of fresh pistachio is used as a postharvest quality indicator. The present study was performed to investigate the chemical properties of fresh pistachios coated with different sodium alginate concentrations (1 and 1.5%), various amounts of Shirazi thyme essential oil (0.3 and 0.5%), and their combination during storage (2 ± 1°C and 85 ± 5% RH). Over the storage duration, chemical parameters were measured on days 13, 26, and 39. The results showed that although the application of sodium alginate in combination with thyme essential oil decreased polyphenol oxidase activity in comparison with other treatments, the highest total phenolics and phenylalanine ammonia lyase activity were found in pistachios coated with alginate (1%) + thyme essential oil (0.3% and 0.5%). In general, it was proven that treatments containing 1% alginate + 0.3% essential oil had the ability to maintain the quality of fresh pistachio fruit approximately over 39 days of storage.

Highlights

Pistachio nuts contain considerable amounts of essential minerals, phenolics, essential fatty acids, proteins, and vitamin A [1] and are known as healthy food
Fruits treated with 0.5% thyme essential oil showed the lowest Total Phenolics (TPs) content (49.91 mg/100 g fresh weight) among all treatments (Figure 1(a))
Certain functional and bioactive compounds can be incorporated into edible coatings, enhancing the safety of coated products and bringing benefits to the health of consumers. us, edible coatings based on the incorporation of active ingredients, especially essential oils, are considered as one of the approaches with the greatest interest for managing the quality of fresh products

Summary

Introduction

Pistachio nuts contain considerable amounts of essential minerals, phenolics, essential fatty acids, proteins, and vitamin A [1] and are known as healthy food. Lipid oxidation, browning, and microbial growth of fresh pistachio play important roles in its final appearance and quality during marketing [3]. After harvesting fresh pistachio, it immediately becomes brown and decayed that affect its final market acceptability [4]. Browning is one of the most important phenomena that occurs in the pistachio hull during processing and storage [3]. It is a common color change among fresh vegetables and fruits and takes place because of the reaction of phenolic compounds, oxygen, and polyphenol oxidase (PPO) enzyme. Biochemical studies have shown that the oxidation of polyphenols (mainly the conversion of ortho-diphenols into quinones and semiquinones) is the reason for hull browning [4]

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Results

Conclusion