1 Introduction

Apple (Malus domestica Borkh.) is an economically important deciduous fruit crop of the temperate region. It can be grown in 54 districts of Nepal, in rain shadow or low rainfall mountainous areas, of which 12 districts grow apple commercially. Jumla district ranks number one in terms of area and production (Subedi et al., 2012) where Red Delicious is the widely adapted commercial cultivar. The district lies in the remote mountain area and just recently it is connected with transportation network. Farmers have not been receiving anticipated level of income because of traditional system of postharvest handling (Subedi et al., 2016). Large amount of fruit losses occurs after harvest and minimizing this loss could save over 25% of the produce (Gurung, 1998). About 58.2% of damage occurs during harvesting, handling, transportation and distribution due to inappropriate practices (Gautam et al., 2002). Corrugated fiber board (CFB) boxes are commonly used packaging material for transported fruit in many developed countries. CFB boxes are capable of withstanding various shipping and transportation hazards, attractive, light in weight; provide good stacking strength, excellent cushioning for product protection, and offers better retention of shelf life; quality fruits and better printability which helps in efficient marketing (D.K. Salunkhe et al., 1995). The size, thickness and stacking strength of CFB box is very important to protect fruit from physical damage during transportation (Gautam et al., 2004). They have suggested 10 kg capacity 5 ply 160 PSI boxes most effective to transport apple from Mustang to Chitwan, Nepal.

At present condition in Jumla, fruits are packed with whole stalk in sacks, bamboo basket and beer cartons for transportation. Nearest cold storage and market outlet is located in Kohalpur, Banke, Nepal which is far (220 km) from the production site. Fruits are usually stored in cold store by traders and released periodically for marketing. This study focused on packaging method for transportation of fruits from collection centre to nearest market. All the damages and injuries may not be visible to naked eyes but they influence weight loss, rotting, quality and shelf-life in long run. Mechanical damages like bruising cuts, puncture, split and abrasion due to scratch, compression impact and vibration forces for instance causes significant economic loss of fruits due to downgrading or rejection of appearance quality by the consumers (Van Zeebroeck et al., 2007). Mechanical damages during transportation and handling accelerate the physiological processes leading to senescence, consequent spoilage and loss of nutritional value. Several studies conducted internationally showed that compression, vibration and impact forces during transportation and handling lead to mechanical damage, reduces quality to consumer and income to fruit industries (Umezuruike et al., 2014). Moreover scratches and wounds created during transport are the avenue for the entry of microorganism for the development of disease and consequent rotting. Such damages may not be apparent and visible to naked eyes right after transport; however effects are apparent during and/or after storage. The sharp tip of the fruit stalk causes scarring damage to apples during handling and long distance transportation. Various packaging materials are elsewhere used to hold apple fruits for transportation. Most of the apples fruits imported from China are individually wrapped with Styrofoam and packed in different CFB box. Existing higher postharvest loss of apple can be effectively minimized by improving packaging method for transportation. The main objective of this study was to identify appropriate packaging method for transportation of apple.

2 Materials and Methods

Studies were carried out for two consecutive years (2013-2014) to identify appropriate packing methods for minimization of transportation loss in Red Delicious apple from production site to distant markets and thereafter in storage. Different packaging treatments were imposed to transport apple fruits from HRS, Rajikot, Jumla to Kohalpur, Banke, Nepal (215 km mountainous gravel road, 48 hours). About 10 kilograms of fruits were packed in CFB boxes (5 ply 160 psi and 300x250x295 mm³) with the following treatments; i. With whole stalk and with trimmed stalk, ii. Individually wrapped with styrofoam and without styrofoam, iii. Fruits arranged in layers separated by deck plate and without deck plate separation and iv. With ventilation and without ventilation. The fruit stalks were trimmed with clipper below the shoulder. Individual fruits were wrapped with styrofoam net. Fruits were arranged in layers separated by 3 ply 120 psi deck plate. Eight holes having 20mm diameter were made in both sides of the CFB boxes for ventilation. The experiment was laid in 4 by 4 factorial design with three replications. All the CFB boxes were sealed with carton tape first, then diagonally sealed by carton sealing and strapping machine (Golden Eagle); transported to truck by porters on their head (200m). CFB boxes were loaded randomly; stacked in 4 layers inside the truck after spreading of HDPE tarpaulin at the base; shipped by truck to Kohalpur, Banke, Nepal. After transportation, fruits were stored as such condition in cold store at 5±1℃ and 95% RH for one month in order to find out the effect as that may not be apparent immediately after transportation.

Observations were recorded on physiological loss in weight (%), total damage (%), unacceptable damage or spoilage (%), acceptable damage (%), total soluble solids (B⁰), firmness (kg force/cm², titratable acidity (%), appearance, crispiness, aroma, taste, juice content, starch index, blush intensity, fruit quality and economic analysis. Consumer’s acceptability was recorded by a panel of 10 judges on the basis of hedonic rating as; 9-like extremely; 8-like very much; 7-like moderately; 6-like slightly; 5-neither like nor dislike; 4-dislike slightly; 3-dislike moderately; 2-dislike very much; 1-dislike extremely (Juyun Lim, 2011). Firmness of fruit was measured with hand penetrometer (FT-327, Italy). Total soluble solids (TSS) were recorded with hand refractometer (Erma, Japan). Titratable acidity (TA) was determined by titrating 5 ml juice with 0.1N sodium hydroxide using phenolphthalein as an indicator and calculated as equivalent maleic acid (AOAC, 1990).

Starch iodine test was performed to determine the conversion pattern of starch into sugars (M.S. Reid et al., 1982). Iodine solution was prepared by dissolving 10 g of iodine crystals and 25 g of potassium iodide in 1 liter of water. The fruits (n=10) were cut at right angles to the core, approximately halfway from stem to calyx end; iodine solution was applied to cut surface, drained away any excess and rated fruit staining after 2 minutes by using 0-6 scales [0-all tissue zones stained (all starch); 1-clearing within the core flesh, particularly between adjacent seed carpel; 2-clearing has extended to the core line and started to extend into the regions between core line vascular bundles; 3-clearing has continued between the core line vascular bundles, while tissue surrounding the core line vascular bundles and in the outer cortex remain stained; 4-clearing has continued into the outer cortex, but not to the skin. Most core line vascular bundles and associated tissue which remain stained are surrounded by unstained cortical tissue; 5-clearing has extended to within a few mm of the skin and unstained zones around the core line vascular bundle, where they exist, started to contract; 6-no staining (no starch)]. Spoilage was considered for unacceptable fruit losses, whereas some fruits which were damaged partially and were accepted at 50% lower price an equivalent loss were calculated. Data were analyzed statistically using MSTATC software version 1.3. Economic analysis of best and existing packing methods were calculated assuming 50% lower price of damaged fruits in the market.

3 Results and Discussions

3.1 Physiological loss in weight (%)

All the imposed treatments had significant effect on PLW of apple (Table 1; Table 2; Table 3; Table 4; Table 5; Table 6; Table 7). PLW was high in the fruits which were transported with untrimmed stalk. PLW was lowered by trimming stalk, keeping fruits in the layers separated by deck plate in the boxes. Irrespective of other treatments, all the fruits kept in ventilated CFB boxes had slightly higher PLW as compared to unventilated condition. Wrapping individual fruits with styrofoam was very much effective to reduce weight loss during transportation and subsequent storage. Interaction effect showed lowest PLW (1.17%) in the fruits which were individually wrapped with styrofoam and transported without ventilation in CFB box, whereas it was highest (2.00%) in fruits which were with untrimmed stalk held in CFB boxes without deck plate separation. Reduction in PLW in unventilated condition was simply due to physical barrier for transpiration. Despite of lower PLW, anaerobic condition may have harmful effect in the quality of fruits if hold for longer period. Styrofoam wrapped fruits remained healthy, undamaged and had minimum PLW. Keeping fruits in layers separated with deck plate minimized vibration damage during transport and thus reduce the PLW. Although PLW was reduced without ventilation, however, in long run with high temperature this may be harmful to fruits as high temperature in anaerobic condition favors fermentation in fruits. Higher PLW in untrimmed fruits was due to physical damage to adjacent fruits resulting higher rate of respiration and transpiration (Shrestha, 1996; Gautam and Bhattarai, 2012). Mohammed et al. (2016) reported that moisture loss of a single bruised apple may be increased by as much as 400% compared to that of an intact apple. 

3.2 Fruit damage (%)

Fruit damage was categorized to total fruit damage, marketable fruit damage and unmarketable fruit damage (spoilage). All the imposed treatments had significant effect on total damage, acceptable damage and spoilage loss of fruits (Table 2; Table 3; Table 4; Table 7). The trend of damage for all three parameters was similar with all the treatments. It was high in the fruits which were transported with untrimmed stalk. This damage was lowered by trimming the stalk, keeping fruits in the layers separated by deck plate in the CFB boxes and wrapping individual fruits with Styrofoam. Wrapping individual fruits with Styrofoam was very much effective to reduce the damage during transportation and subsequent storage. The fruits kept in ventilated CFB boxes had slightly lower total damage as compared to unventilated condition. Interaction effect showed lowest total damage (3.44%) in the fruits which were individually wrapped with styrofoam, transported with ventilation in CFB box, keeping fruits in the layers separated by deck plate in the boxes compared to other treatments. Styrofoam wrapped fruits remained healthy and had minimum total damage. Keeping fruits in layers separated with deck plate minimized vibration damage during transport and thus reduce the total damage. Higher damage and spoilage loss in untrimmed fruits might be due to physical damage to adjacent fruits resulting higher rate of respiration, transpiration and microbial infection (Shrestha, 1996; Gautam and Bhattarai, 2012).

Keeping fruits individually in styrofoam and in layers separated with deck plate inside the box minimized vibration damage during transport and thus reduce the spoilage damage. Wilson et al. (1999) reported that detrimental effect of mechanical injury is not restricted to visual aspects but higher risk of bacterial and fungal contamination leading to a lower shelf life. Studman (1997) reported that apple bruising can result in product losses up to 50%, although typically loss levels are in the 10-5% range, depending on consumer awareness. Bruising is the major postharvest mechanical damage problem during fruit transport and handling. Mechanical injury accelerates the infection of fungal diseases predominantly gray mold (Botrytis) or blue mold (Penicillium), which cannot infect healthy tissue and typically enter through dead or wounded tissue before contaminating the rest of the fruit. Mechanical injury could be the most important cause of defects and diseases. If mechanical injury could be avoided to prevent disease and there would be much less loss of fruit (Knee and Miller, 2002).

3.3 Total postharvest loss (%)

Total postharvest loss was calculated based on PLW + spoilage loss + equivalent loss in marketable damaged fruits (Table 1; Table 3; Table 5; Table 7). Damaged fruits are usually sold in market at 50% lower price. Equivalent loss was calculated based on 50% price of the damaged fruits. The trend of equivalent loss was same as spoilage fruits. The result show there is significant effect of stalk trimming, styrofoam, deck plate separation and ventilation on minimization of total postharvest loss during transportation and storage. The effect of styrofoam was most effective (6.08%), followed by deck plate separation (6.85%), trimming (8.10%) and ventilation (9.60%). Interaction effect showed that the equivalent loss was lowest (0.4%) in stalk trimmed fruits individually wrapped with styrofoam kept in CFB boxes and separated by the deck plate. Total postharvest loss was lowest (3.8%) in individually styrofoam wrapped trimmed fruits held in ventilated CFB boxes with deck plate separation followed and was found highest (18.2%) in untrimmed fruits which were kept without ventilation. Although the effect of ventilation was not much in this study in long run this may be harmful as high temperature in anaerobic condition favors fermentation in fruits.

3.4 Fruit quality

The quality of fruits like blush intensity, appearance, crispiness, aroma, taste, firmness, juice content, starch content, TSS, TA and TSS/TA ratio of healthy fruits was not affected by the packaging methods during transportation and storage (Table 8; Table 9).

3.3 Economic analysis

Postharvest loss (3.8%) was minimum in the fruits which were packed in CFB boxes arranged in layers separated by deck plate, wrapping of individual fruits by styrofoam, trimming of fruit stalk and making ventilation on both sides of CFB box while maximum (18.2%) in the fruits which were packed in CFB boxes without deck plate, without wrapping of individual fruits by styrofoam, without trimming of stalk and without ventilation (Table 10; Table 11). Lowest net return (NRs.191250/truckload) was observed with conventional method while highest (NRs.286500/ truckload) with improved method. With prospects of loss reduction, improved method sounds the best technology. PLW (2.0%), total damage (19.55%), spoilage loss (12.75%), acceptable damage (6.80%) and losses due to 50% decrease in the market value of the fruits was 3.4% with conventional method making a total of 18.2% postharvest loss which was reduced to 3.8% with improved method. Economic analysis shows that higher benefit cost ratio (1.78) with improved method as compared to conventional method (1.60). If the traders replace the conventional packing method by improved one, they can gain additional benefit of NRs. 95250 (US $ 899) per truckload.

4 Conclusions

Based on the above results, we can conclude that packaging of apple fruits in CFB boxes arranging in layers separated by deck plate, wrapping of individual fruits with styrofoam, trimming of fruit stalks and making proper ventilations was the appropriate packaging method for transportation of apples from production sites to distant markets and warehouse by truck. This method is most desirable, efficacious and can be accepted by farmers groups, cooperatives, traders and consumers in Nepalese context because of minimum postharvest loss due to low scratching, brushing and spoilage damage; better retention of physical appearance, crispiness, taste, aroma, firmness and juice content; high storability; high net return; high benefit cost ratio, convenience in handling and affordable price for the consumers. Thus, packaging of apple fruits in CFB boxes of 5 ply 160 psi, 10kg capacity by using deck plate between layers, wrapping individual fruits with styrofoam, trimming of stalks and making proper ventilation in the CFB box has high shock bearing capacity during long distance transportation in rough road. Economic analysis shows that if the traders replace the conventional system of packaging fruits by improved one, they can gain additional benefit of NRs. 95250 (US $ 899) per truckload. Higher packaging cost could be an important obstacle in adoption of improved technology, hence provision can be made from the government to subsidize for packaging materials to encourage adoption of improved technology.

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