To study the effect of edible coating materials on shelf-life and storage behaviour of custard apple (Annona squamosa L.) under ambient condition

Introduction

Custard apple (Annona squamosa L.), belonging to the family Annonaceae, is one of the important tropical fruits grown in India. It is widely consumed in fresh form due to its pleasant flavour, sweet taste and high nutritional value. The fruit is characterized by a creamy white pulp rich in carbohydrates, vitamins and minerals, making it a valuable dietary fruit (Rathore, 2018) [8] . Custard apple is considered one of the most important arid and semi-arid fruit crops and is extensively cultivated in Maharashtra, Chhattisgarh, Madhya Pradesh, Andhra Pradesh, Telangana and Rajasthan. India is among the leading producers of custard apple, and the crop contributes significantly to the livelihood of small and marginal farmers in many regions (Reddy et al., 2014) [9] . Custard apple is an excellent source of energy and nutrients. The pulp contains appreciable amounts of sugars, vitamin C, dietary fibre and essential minerals. Owing to its unique flavour and nutritional richness, the fruit has gained considerable consumer preference and commercial importance in recent years (Dash et al., 2021) [2] . However, custard apple is highly perishable in nature due to its climacteric pattern of ripening, high respiration rate and rapid softening after harvest. Under ambient conditions, the fruits undergo rapid physiological and bio-chemical changes, leading to deterioration in quality, reduced shelf-life and increased post-harvest losses. The fruits are also highly susceptible to microbial spoilage, which further limits their storage and marketability (Rathore, 2018) [8] . Edible coatings are eco-friendly post-harvest treatments that form a thin protective layer on the fruit surface and help regulate moisture loss and gas exchange. These coatings reduce respiration rate, delay ripening and maintain the bio-chemical and sensory quality of fruits during storage. Among the various edible coating materials, Aloe vera gel, bee wax, sago starch and chitosan have shown promising results in preserving fruit quality and extending shelf life (Mahajan et al., 2005) [6] .

An edible coating acts as a semi-permeable barrier between the fruit and the surrounding environment, thereby reducing water loss and delaying senescence. Due to their biodegradable, non-toxic and safe nature, edible coatings are increasingly being used as an effective alternative to synthetic chemicals for maintaining post-harvest quality and extending the storage life of fruits (Khaliq et al., 2015) [5] . Therefore, the present investigation was undertaken to study the effect of edible coating materials on shelf-life and storage behaviour of custard apple (Annona squamosa L.) under ambient condition. The study was aimed at evaluating the influence of different edible coating materials on biochemical parameters and identifying the most effective treatment for maintaining fruit quality and extending shelflife under ambient storage condition.

Materials and Methods

Fresh, mature and uniform-sized custard apple fruits were procured for the experiment and brought to the Processing Laboratory, Department of Fruit Science, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.). The fruits were carefully sorted to remove damaged, diseased and injured fruits. Healthy and uniform fruits were selected and subjected to different edible coating treatments. The experiment was conducted during the year 2025-26 in a Completely Randomized Design (CRD) with thirteen treatments and three replications. Different edible coating materials comprising Aloe vera gel, bee wax, sago starch and chitosan at their respective concentrations were prepared and applied uniformly on the fruit surface. After coating, the fruits were allowed to dry at room temperature and subsequently stored under ambient condition. The fruits were evaluated for bio-chemical parameters viz., total soluble solids (°Brix), titratable acidity (%), ascorbic acid (mg/100 g), total sugars (%), reducing sugars (%), nonreducing sugars (%), TSS: acid ratio and Sugar:acid ratio were recorded at 2 days interval during storage. The experimental data were subjected to statistical analysis following the procedures of Completely Randomized Design (CRD). Aloevera gel @ 10% T1 3.

Results and Discussions 3.1 Bio-chemical parameters of custard apple fruits

The bio-chemical characteristics of custard apple fruits were determined by recording total soluble solids (°Brix), titratable acidity (%), ascorbic acid content (mg/100 g pulp), total sugars (%), reducing sugars (%), non-reducing sugars (%), TSS: acid ratio and sugar: acid ratio.

Total Soluble Solids (°Brix)

The variation in total soluble solids of custard apple fruits during storage revealed that T₆ (Chitosan @ 2%) maintained the maximum TSS (20.65, 24.50, 27.05 and 27.80 °Brix) at 2nd, 4th, 6th and 8th days after storage, respectively. The minimum TSS (16.82 and 20.02 °Brix) was noticed in T₀ (control) at 2nd and 4th days, respectively, whereas at 6th day, the minimum value (23.45 °Brix) was recorded in T₁₀ (Bee wax @ 1%). At 8th day, fruits were retained only under T₆. The similar findings are in close conformity with those reported by Golhani et al. (2013) [4] in custard apple.

The minimum titratable acidity (0.29, 0.24 and 0.21%) was recorded in T₆ (Chitosan @ 2%) at 2nd, 4th and 6th days after storage, respectively. On the other hand, the maximum acidity (0.46 and 0.41%) was observed in T₀ (control) at 2nd and 4th days, respectively, while at 6th day, the maximum value (0.38%) was registered under T₁₀ (Bee wax @ 1%). At 8th day, fruits were available only in T₆. The similar findings are in close conformity with those reported by Padmaja et al.

(2014) [7] in sapota, Valero et al. (2013) [10] in table grapes and Ali et al. (2011) [1] in papaya.

The ascorbic acid content exhibited a decreasing trend with advancement of storage period. The maximum ascorbic acid content (42.36, 41.56, 39.03 and 36.75 mg/100 g) was recorded in T₆ (Chitosan @ 2%) at 2nd, 4th, 6th and 8th days, respectively. The minimum values (34.42 and 27.08 mg/100 g) were observed in T₀ (control) at 2 nd and 4th days, respectively, while at 6th day, the minimum value (30.49 mg/100 g) was recorded under T₁₀ (Bee wax @ 1%).

The total sugar content of custard apple fruits varied considerably during storage. The maximum total sugar content (21.82, 22.35 and 24.78%) was obtained under the treatment T₆ (Chitosan @ 2%) at 2nd, 4th and 6th days after storage, respectively. The minimum values (17.24 and 18.98%) were recorded under T₀ (control) at 2nd and 4th days, respectively, whereas at 6th day, the minimum value (21.54%) was observed in T₁₀ (Bee wax @ 1%). At 8th day, T₆ recorded 19.00% total sugars. Similar findings have been reported by Vahdat et al. (2010) [11] in strawberry.

A gradual change in reducing sugar content was observed during the storage period. The maximum reducing sugar content (16.32, 16.53, 18.74 and 20.04%) was recorded under the treatment T₆ (Chitosan @ 2%) at 2nd, 4th, 6th and 8th days after storage, respectively. The minimum reducing sugar content (13.12 and 14.82%) were registered in T₀ (control) at 2nd and 4th days, respectively, while at 6th day, the minimum reducing sugar content (16.16%) was found under the treatment T₁₀ (Bee wax @ 1%).

The non-reducing sugar content of the fruits differed among the treatments throughout the storage period. The maximum non-reducing sugar content (5.50, 5.82, 6.08 and 6.12%) was recorded under the treatment T₆ (Chitosan @ 2%) at 2nd, 4th, 6th and 8th days after storage, respectively. The minimum non-reducing sugar content (4.12 and 4.16%) were noted under the treatment T₀ (control) at 2nd and 4th days, respectively, whereas at 6th day, the minimum non-reducing sugar content (5.38%) was recorded under T₁₀ (Bee wax @ 1%). At 8th day, fruits were retained only under T₆.

TSS: acid ratio

The TSS: acid ratio of custard apple fruits varied significantly among the treatments during storage. The maximum TSS: acid ratio (71.20, 102.08, 128.80 and 163.52) was recorded under the treatment T₆ (Chitosan @ 2%) at 2nd, 4th, 6th and 8th days after storage, respectively. The minimum TSS: acid ratio (36.56 and 48.82) were recorded under the treatment T₀ (control) at 2nd and 4th days, respectively, whereas at 6th day, the minimum value (61.71) was observed under T₁₀ (Bee wax @ 1%). At 8th day, fruits were retained only under T₆. The present findings are close conformity with the findings reported by Golhani and Bisen et al. (2012) [3] in custard apple, Padmaja et al. (2014) [7] in sapota and Vyas et al.

Sugar: acid ratio

The sugar: acid ratio showed considerable variation among the treatments throughout the storage period. The maximum sugar: acid ratio (75.24, 93.12, 117.61 and 153.88) was recorded under the treatment T₆ (Chitosan @ 2%) at 2nd, 4th, 6th and 8th days after storage, respectively. The minimum sugar: acid ratio (37.47 and 46.29) were observed under the treatment T₀ (control) at 2nd and 4th days. At 6th day, the minimum value (56.68) was recorded under the treatment T₁₀ (Bee wax @ 1%). At 8th day, only T₆ retained fruits. 3) NS: Non-significant 4) The superscript letters signifies that the treatment means with similar letters are at par at 5% level of significance, while the means with different letters are significantly different at 5% level of significance. These letters have been affixed based on CD-value comparison of treatment means. DAS: Days after storage, Value marked as * indicates fruits get spoiled, NS: Non-significant, The superscript letters signifies that the treatment means with similar letters are at par at 5% level of significance, while the means with different letters are significantly different at 5% level of significance. These letters have been affixed based on CD-value comparison of treatment means. The superscript letters signifies that the treatment means with similar letters are at par at 5% level of significance, while the means with different letters are significantly different at 5% level of significance. These letters have been affixed based on CD-value comparison of treatment means.

Conclusions

The study revealed that edible coating treatments had a significant influence on the bio-chemical parameters of custard apple during ambient storage. Coated fruits showed better retention of bio-chemical quality in terms of TSS, total sugars, reducing sugars, non-reducing sugars, ascorbic acid and TSS: acid ratio and sugar: acid ratio along with comparatively lower changes in acidity as compared to the untreated fruits. Among the different treatments, chitosan @ 2% (T6) was found to be the most effective in maintaining the bio-chemical quality of custard apple, followed by chitosan 1.5% (T5). The untreated fruits (T0) showed comparatively faster deterioration in bio-chemical quality during storage. Thus, chitosan @ 2% coating was found to be the most effective treatment for maintaining the bio-chemical quality of custard apple under ambient storage condition.

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