نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Lime fruits undergo metabolic changes during storage, resulting in peel dehydration and loss of green color, which adversely affect their marketability. To preserve fruit quality and delay postharvest senescence, various edible coatings and natural bioactive compounds have been investigated. In this study, a factorial experiment based on a completely randomized design was conducted to evaluate the effects of postharvest immersion in 0.1% and 0.2% commiphora myrrha and 1% pomegranate peel extract, applied individually or in combination, on the quality of mature green lime fruits during 24 days of storage at 25 ± 2 °C.
The results showed that treatment with 0.1% commiphora myrrha significantly reduced fruit weight loss compared with the control. This treatment also maintained the highest titratable acidity (TA) (12.17%), whereas the control fruits exhibited the lowest TA (10.88%). The lowest total soluble solids (TSS) content was recorded in fruits treated with 1% pomegranate peel extract, while the highest TSS was observed in the control. Moreover, fruits treated with commiphora myrrha and pomegranate peel extract retained higher ascorbic acid content and exhibited greater antioxidant capacity than the untreated control. Overall, both commiphora myrrha and pomegranate peel extract effectively maintained the physicochemical quality of lime fruits throughout storage, as confirmed by the superior visual appearance of the treated fruits. These findings indicate that the application of commiphora myrrha and pomegranate peel extract is a promising postharvest strategy for preserving the quality and extending the marketability of lime fruits during storage.
کلیدواژهها English
Extended Abstract
Introduction
Postharvest losses of citrus fruits, particularly lime, remain a major challenge in tropical and subtropical regions because fruit quality rapidly deteriorates during handling, storage, and transportation. Among the various postharvest technologies, edible coatings have attracted considerable attention as an effective and environmentally friendly approach to extending fruit shelf life. By forming a thin protective barrier on the fruit surface, these coatings reduce moisture loss, limit oxygen diffusion, and inhibit microbial growth, thereby preserving the physicochemical, nutritional, and sensory quality of fresh produce.
Incorporating natural plant extracts into edible coatings further enhances their functionality by providing antioxidant and antimicrobial activities. Myrrh gum resin (Commiphora myrrha), a natural exudate with a long history of medicinal use, possesses strong antimicrobial and antioxidant properties that contribute to delaying postharvest deterioration. Likewise, pomegranate (Punica granatum L.) peel, an abundant agricultural byproduct, is a rich source of polyphenols, flavonoids, and other bioactive compounds with remarkable free radical scavenging and antimicrobial activities. The utilization of these natural materials in edible coating formulations is consistent with the increasing consumer preference for safe, biodegradable, and sustainable alternatives to synthetic chemical preservatives.
Therefore, the development of plant-based edible coatings enriched with myrrh gum resin and pomegranate peel extract represents a promising strategy for reducing postharvest losses, maintaining fruit quality, and promoting environmentally sustainable practices in the fresh produce industry.
Material and methods
Mature green lime fruits (Citrus aurantifolia) were harvested from a commercial orchard in the Rudkhan region of Rudan County, Hormozgan Province, Iran (27°59′ N, 57°29′ E). Fruits of uniform size and free from visible defects or mechanical damage were selected for the experiment. After harvest, the fruits were washed thoroughly and disinfected by immersion in a 0.05% sodium hypochlorite solution for 1 min.
Myrrh (Commiphora myrrha) gum resin solutions were prepared at concentrations of 0.1% and 0.2% (w/v) by dissolving the gum resin in distilled water with continuous stirring at room temperature for 30 min. A 1% (w/v) pomegranate peel extract solution was prepared using the same procedure. The fruits were immersed in the respective coating solutions for 10 min, allowed to air-dry at room temperature, and then packed in disposable plastic containers. All samples were stored at 25 ± 2 °C for 24 days.
At the end of the storage period, fruit quality was evaluated by measuring several physicochemical and biochemical attributes. Ascorbic acid content was determined using the indophenol titration method, total phenolic content was measured using the Folin–Ciocalteu assay, and antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Fruit appearance was also evaluated based on peel color, freshness, and surface gloss.
The experiment was arranged as a factorial experiment in a completely randomized design (CRD), and the data were analyzed using SAS software (version 9.4).
Results and discution
Fruit weight loss increased progressively throughout the storage period in all treatments; however, coated fruits consistently exhibited lower weight loss than the untreated control. At the end of storage, the highest weight loss was observed in the control fruits (28.5%), whereas the lowest value (21.5%) was recorded in fruits treated with 0.1% myrrh (Commiphora myrrha) gum resin, indicating its effectiveness in reducing moisture loss. The reduced transpiration and respiration rates resulting from the protective barrier formed by the edible coatings likely contributed to this improvement.
Total soluble solids (TSS) increased gradually during storage, reflecting the normal ripening process and the conversion of reserve carbohydrates into soluble sugars. The increase was significantly greater in the control fruits, while the lowest TSS value (6.83%) was observed in fruits treated with 1% pomegranate peel extract. In contrast, coated fruits maintained significantly higher titratable acidity (TA) than the control, with the 0.1% myrrh gum resin treatment showing the highest TA (12.17%) at the end of storage. These findings suggest that the coatings effectively slowed metabolic activity and delayed fruit senescence.
Ascorbic acid content declined in all treatments during storage; nevertheless, coated fruits retained significantly higher levels than the control. Fruits treated with pomegranate peel extract exhibited the highest ascorbic acid content (62 mg/100 mL), whereas the control fruits showed the lowest value (20.66 mg/100 mL). Similarly, the combination of 0.1% myrrh gum resin and pomegranate peel extract resulted in the highest total phenolic content (4.01 mg g⁻¹), demonstrating the ability of these natural coatings to preserve antioxidant compounds during storage. The higher antioxidant activity observed in the treated fruits may be attributed to the abundance of phenolic compounds in pomegranate peel extract together with the bioactive constituents of myrrh gum resin, which reduce oxidative damage by scavenging reactive oxygen species.
Visual quality was also markedly improved by the coating treatments. Fruits coated with myrrh gum resin, either alone or in combination with pomegranate peel extract, maintained a greener peel, greater surface gloss, and a fresher appearance than the untreated fruits. In contrast, the control fruits exhibited severe dehydration, peel shriveling, and pronounced yellowing, resulting in poor marketability.
Overall, the application of myrrh (Commiphora myrrha) gum resin and pomegranate peel extract effectively preserved the physicochemical, biochemical, and visual quality of lime fruits during ambient storage. These natural coatings reduced weight loss, delayed ripening, maintained organic acids and antioxidant compounds, and significantly enhanced fruit appearance. The results demonstrate that myrrh gum resin and pomegranate peel extract are promising, environmentally friendly postharvest treatments for extending shelf life and reducing postharvest losses of lime fruits.
Conclusion
The application of edible coatings based on Commiphora myrrha gum resin and pomegranate peel extract effectively preserved the postharvest quality of lime fruits under ambient storage conditions. These treatments significantly reduced weight loss, maintained higher titratable acidity (TA), moderated the increase in total soluble solids (TSS), and improved the overall marketability of the fruits. In addition, coated fruits retained higher ascorbic acid content, total phenolic content, and antioxidant activity than the untreated control, indicating a greater capacity to delay oxidative deterioration during storage. The coatings also preserved the visual quality of the fruits by maintaining peel greenness, surface gloss, and overall freshness, whereas the control fruits exhibited severe dehydration and yellowing.
Overall, the results demonstrate that Commiphora myrrha gum resin and pomegranate peel extract are effective natural coating materials for maintaining the physicochemical, biochemical, and visual quality of lime fruits. Their application represents an environmentally friendly and sustainable postharvest strategy for extending shelf life, enhancing marketability, and reducing postharvest losses.
Data Availability Statement
The authors declare that all the data supporting the findings of this research are available within the article.
Ethical considerations
This article does not contain any studies involving human and animal subjects.
Conflict of 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.
