Effects of edible coatings of Chlorella sp. containing pomegranate seed oil on quality of Spondias tuberosa fruit during cold storage

Biodegradable Film Is Enriched with Pomegranate Seed Oil and Microalgae for Preservation of Cajarana (Spondias dulcis)

This study aimed to develop and characterize biodegradable films made from pectin, pomegranate seed oil, and different microalgae (Spirulina platensis, Chlorella sp., and Scenedesmus obliquus) and to evaluate their applicability as packaging by verifying their effect on the conservation and postharvest quality of cajarana (Spondias dulcis). The films proposed in this study were assessed for their physical, optical, and mechanical attributes, as well as the physicochemical characteristics of the fruits coated with the films after 14 days of storage at 10 ± 1 °C and relative humidity of 60 ± 5%. Incorporating microalgae improved the homogeneity and mechanical properties, decreasing breaking stress, elastic modulus, and maximum tensile strength, contributing to a lower solubility and improving the barrier properties of the films compared to the control (T1). The film formulated with 6% citric pectin, 40% glycerin, 0.5 mL·L-1 pomegranate seed oil (PSO), and 0.05% Scenedesmus obliquus showed better performance in solubility, water vapor permeability (WVP), and mechanical properties, maintaining gloss and transparency, approaching the performance of the commercial PVC film. The film was formulated with 6% pectin + 40% glycerin + 0.5 mL·L-1 PSO + 0.05% Chlorella sp. maintained the postharvest quality of cajarana fruits, allowing the conservation of the physicochemical quality of the fruits after 14 days of storage at 10 ± 1 °C and 60 ± 5% RH.

Enhancing Mexican lime (Citrus aurantifolia cv.) shelf life with innovative edible coatings: xanthan gum edible coating enriched with Spirulina platensis and pomegranate seed oils

BACKGROUND

The Mexican lime (Citrus aurantifolia cv.), widely consumed in Iran and globally, is known for its high perishability. Edible coatings have emerged as a popular method to extend the shelf life of fruits, with xanthan gum-based coatings being particularly favored for their environmental benefits. This study aims to evaluate the effectiveness of an edible coating formulated from xanthan gum, enriched with Spirulina platensis (Sp) and pomegranate seed oil (PSO), in improving the quality and reducing the weight loss of Mexican lime fruit under conditions of 20 ± 2 °C and 50-60% relative humidity.

RESULTS

Based on the results, the application of coatings was generally effective in reducing fruit weight loss, with the least weight loss observed in the xanthan gum 0.2%+ Spirulina platensis extract (1%) treatment. Additionally, the levels of total phenols and flavonoids in the treated fruits exceeded those in the control group, with xanthan gum 0.2%+ Spirulina platensis extract (1%) and xanthan gum 0.2% exhibiting the highest concentrations of these compounds. The antioxidant capacity of the fruits was also enhanced by the coatings, surpassing that of the control group, with xanthan gum 0.2%+ Spirulina platensis extract (1%) achieving the highest levels. The treatments significantly suppressed the activity of the polyphenol oxidase (PPO) enzyme, with xanthan gum 0.2% demonstrating the most potent inhibitory effect. Furthermore, the treatments resulted in increased activities of catalase (CAT) and peroxidase (POD) enzymes compared to the control. Except for xanthan gum 0.2%+ pomegranate seed oil (0.05%), all treatments maintained the fruit's greenness (a*) more effectively than the control.

CONCLUSIONS

Peel browning is a major factor contributing to the decline in quality and shelf life of lime fruit. The application of 0.1% and 0.2% xanthan gum coatings, as well as a combination of 0.2% xanthan gum and Spirulina platensis extract, significantly inhibited PPO activity and enhanced the activity of CAT and POD and phenolic compound in Mexican lime fruits stored at of 20 ± 2 °C for 24 days. Consequently, these treatments comprehensively preserved lime fruit quality by significantly reducing browning, maintaining green color, and preserving internal quality parameters such as TA, thereby enhancing both visual appeal and overall fruit quality.

Multifunctional konjac glucomannan/xanthan gum self-healing coating for bananas preservation

Damage to the integrity of the preservation coating on the fruit surface will seriously affect the shelf life of the fruit. In this work, the strong hydrogen bond interaction between xanthan gum (XG) and konjac glucomannan (KGM) could form hydrogel films with self-healing properties. The introduction of gallic acid (GA) was beneficial to further improve the antioxidant activity and UV shielding performance of the composite films. Surprisingly, the mechanical properties and gas (water vapor, O2 and CO2) barrier properties of the KGM film crosslinked by XG were significantly improved. The experiment of banana preservation showed that the composite coating could effectively delay the water loss and browning of bananas, slow down the decomposition of pectin and starch in the flesh, and extend the shelf life of bananas for >6 days. Therefore, this multifunctional coating is an excellent packaging material and has a very broad application prospect in the field of food preservation.

Evaluation of the quality features of electrospray-coated pineapple slices with pomegranate and grape seed oil-enriched emulsions

The quality characteristics of pineapple slices coated with emulsions enriched with pomegranate seed oil (PSO) and grape seed oil (GSO) by electrospray coating (ESC) and dip-coating (DC) methods were investigated. The ESC method was evaluated as an alternative to conventional DC. Pineapple slices were stored in clear polystyrene cups for seven days at 5 °C and 80% RH. The weight loss (%), pH, titratable acidity, color, firmness, total antioxidant activity (TAA), total phenolic content (TPC), microbiological, and sensory qualities of fresh-cut pineapple slices were evaluated. Coated samples had significantly lower weight loss values than the non-coated samples after 7 days of storage. The usage of GSO-enriched emulsion with the ESC method was found to be more successful in preserving the titratable acidity. Although all the samples exhibited a significant decrease in yellowness (b*), the electrospray-coated pineapple slices had the highest. Incorporating GSO into the emulsions helped protect the tissue of the fresh-cut pineapples, regardless of the coating method used. The TPC and TAA values of the samples coated by the ESC method with emulsions enriched with PSO showed a lower decrease compared to other treatments. It was determined that the ESC method was more successful in preserving the sensory qualities of fresh-cut pineapples. These findings suggested that using ESC as a coating method with EO-enriched emulsions has positive effects on the quality features of fresh-cut pineapples.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05839-4.

Latest Developments in Edible Coatings on Minimally Processed Fruits and Vegetables: A Review

The food industry nowadays is facing new challenges in terms of sustainability and health implications of packaging and processing techniques. Due to their desire for new and natural products coupled with changes in lifestyle, consumers are looking for food products that have been less processed but possess longer shelf life and maintain nutritional and sensorial proprieties during storage. These requirements represent real challenges when dealing with highly perishable food products, such as fruits and vegetables. Thus, in recent years, edible coatings have been intensively developed and studied because of their capacity to improve the quality, shelf life, safety, and functionality of the treated products. Edible coatings can be applied through different techniques, like dipping, spraying, or coating, in order to control moisture transfer, gas exchange, or oxidative processes. Furthermore, some functional ingredients can be incorporated into an edible matrix and applied on the surface of foods, thus enhancing safety or even nutritional and sensory attributes. In the case of coated fruits and vegetables, their quality parameters, such as color, firmness, microbial load, decay ratio, weight loss, sensorial attributes, and nutritional parameters, which are very specific to the type of products and their storage conditions, should be carefully monitored. This review attempts to summarize recent studies of different edible coatings (polysaccharides, proteins, lipids, and composites) as carriers of functional ingredients (antimicrobials, texture enhancers, and nutraceuticals) applied on different minimally processed fruits and vegetables, highlighting the coating ingredients, the application methods and the effects on food shelf life and quality.

An Extensive Review of Natural Polymers Used as Coatings for Postharvest Shelf-Life Extension: Trends and Challenges

Global demand for minimally processed fruits and vegetables is increasing due to the tendency to acquire a healthy lifestyle. Losses of these foods during the chain supply reach as much as 30%; reducing them represents a challenge for the industry and scientific sectors. The use of edible packaging based on biopolymers is an alternative to mitigate the negative impact of conventional films and coatings on environmental and human health. Moreover, it has been demonstrated that natural coatings added with functional compounds reduce the post-harvest losses of fruits and vegetables without altering their sensorial and nutritive properties. Furthermore, the enhancement of their mechanical, structural, and barrier properties can be achieved through mixing two or more biopolymers to form composite coatings and adding plasticizers and/or cross-linking agents. This review shows the latest updates, tendencies, and challenges in the food industry to develop eco-friendly food packaging from diverse natural sources, added with bioactive compounds, and their effect on perishable foods. Moreover, the methods used in the food industry and the new techniques used to coat foods such as electrospinning and electrospraying are also discussed. Finally, the tendency and challenges in the development of edible films and coatings for fresh foods are reviewed.