Impact damage to apple fruits in commercial corrugated fiberboard box packaging evaluated by the pressure-sensitive film technique

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1 WFL Publisher Science and Technology Meri-Rastilantie 3 B, FI-98 Helsinki, Finland info@world-food.net Journal of Food, Agriculture & Environment Vol.8 (2): Impact damage to apple fruits in commercial corrugated fiberboard box packaging evaluated by the pressure-sensitive film technique Fei Lu, 2, Yutaka Ishikawa 2 *, Hiroaki Kitazawa 2 and Takaaki Satake 3 College of Food Science and Technology, Shenyang Agricultural University, No. 2 Dongling Road, Shenyang, Liaoning 866, China. 2 Food Packaging Laboratory, Food Engineering Division, National Food Research Institute, 2--2, Kannondai, Tsukuba, Ibaraki , Japan. 3 Graduate School of Life and Environmental Sciences, University of Tsukuba, - -, Tennodai, Tsukuba, Ibaraki , Japan. * yishi@affrc.go.jp Received 7 January, accepted 22 March. Abstract During transport and handling, apple fruits experience a variety of loading conditions that potentially lead to damage and bruising. New methods were analyzed for assessing and predicting apple bruising that occurs in corrugated fiberboard boxes due to impact loads during the course of transport and handling. Impact pressure and bruising of apples using a pressure-sensitive film technique were measured by a simple drop test. The statistical incidence of damage and damaged areas for the apples in two types of commercial corrugated fiberboard boxes after being subjected to dropping impact loads were compared: single-wall corrugated fiberboard box and double-wall corrugated fiberboard box. The percentage of damaged apples in the single-wall and double-wall corrugated boxes increased with the increase in drop height; the damage to apples in the lower layer of both boxes was notably higher than that in the upper layer. The images of the pressure-sensitive films showed significant differences in apples impact in both types of boxes. The pressured area of apples in the single-wall corrugated fiberboard box was greater than that in the double-wall corrugated fiberboard box. For both boxes, the pressured area increased on the pressure-sensitive film with the increase in drop height. The average pressure in the single-wall corrugated fiberboard box was slightly greater than that in the double-wall corrugated fiberboard box. In the case of both boxes, no significant change in the average pressure was found as a result of drop height; the change in the average pressure between the upper and lower layers was also not significant. The results indicate that the impact force obtained from the pressure-sensitive film (F PSF ) can be used to assess and predict apple bruising that occurs in corrugated fiberboard boxes. The coefficients of determination (R 2 ) for single-wall, double-wall and both corrugated fiberboard boxes were.94,.85 and.86, respectively. Key words: Apple, impact bruising, pressure-sensitive film, corrugated fiberboard box packaging. Introduction During transport and handling, fruits and vegetables experience a variety of loading conditions that potentially lead to damage and bruising. Mechanical damage can reduce the quality of such products and in Japan, losses during transport and distribution were about 7% for fruits and % for vegetables in 7 2. Much research has been conducted on the effect of packaging on apple fruit bruising, focusing on packaging materials 3-8 and various types of packaging 9-2. To predict apple bruising caused by impact onto different cushioned surfaces, Chen and Yazdani developed a model based on the parameters solely derived from acceleration, impacting mass data and Fourier-transform coefficients of the impact acceleration curves 5. Jarimopas et al. 6 developed a simplified ballistic pendulum test method that can be used to measure impact resistance strength characteristics of apples or other fruits and evaluated various cushioning materials that can provide shock protection. Using a sampling and compression test, Peleg defined the performance tolerance intervals of regular corrugated shipping containers for apples and investigated the effects of different types of internal partitions and strength reduction due to hand holes 2. Holt and Schoorl compared three different types of packaging for their protection afforded to apples against dropping impact loads. They found that tray packs gave the best protection, followed by returnable crates, and then wooden boxes 4. Furthermore, Holt and Schoorl developed an energy model of the bruising process for impacted multilayered single columns of apples to quantify the effects of potholes and bumps as well as the effects of soft and hard suspensions 5. Alternatively, Timm et al. 7 examined damage to apples in bulk bins during semi-trailer transport and found that apples in plastic bins had much less abrasion damage than those in hardwood and plywood bins, while Acıcan et al. 2 studied the mechanical forces exerted on apples in wooden crates during transport from harvest to market, as well as damage caused by these forces. They used the means of free fall, horizontal impact and vibration forces to calculate the mechanical forces acting on the crates during transport 2. However, comparison of the degree of damage to fruits among these previous studies is difficult, as damage was measured using different packaging systems comprising varying cushioning 28 Journal of Food, Agriculture & Environment, Vol.8 (2), April

2 materials, based on specific transport and handling conditions. Therefore, a more universal method needs to be developed for analysis of fruit damage under different transport or handling conditions. We recently measured the impact pressure and bruising of apples resulting from impact loads using a pressuresensitive film and developed a bruise predicting method using regression models based on the impact force obtained from this pressure-sensitive film (F PSF ) 22, 23. Further examination of fruit damage due to impact loads that occurs in actual packaging used during transport (e.g. a corrugated fiberboard box with cushioning material used in Japan) is now required to confirm the applicability of this technique. The present study therefore used the non-invasive pressuresensitive film technique to measure the impact pressure and pressure distribution of impacted apple fruit packaged in two types of commercial corrugated fiberboard boxes. The nature of the resulting bruises on the fruit was also examined in order to develop a method for assessing and predicting apple bruising based on pressure data obtained from the pressure-sensitive film. Materials and Methods Apples: All experiments were carried out with Fuji cultivar apple fruits harvested in November 7 from Yamagata Prefecture, Japan. Apples were selected for uniformity of size, ground color and firmness, as well as freedom from defects and mechanical damage. The average weight of the apples was ±.3 g. The apple fruits were stored at 4 C in air until tested in June 8. The selected apples were considered to not be turgid and therefore, to have low damage probability. Packaging types: Two types of commercial corrugated fiberboard boxes used in Japan were compared in this study: single-wall (SWCFB) and double-wall corrugated fiberboard box (DWCFB). The packaging used in this study is shown in Fig.. Apples were placed into the corrugated fiberboard boxes in two layers of 2 fruit, for a total of 4 fruit per box. Each box was a regular slotted container (RSC) coded 2. The inside dimensions of both boxes were 43 mm 37 mm 8 mm. Fig. d shows the cushioning material used: a plastic tray manufactured from A-PET. (c) (d) Figure. Packaging used in this study: schematic side view; actual top view; (c) corrugated fiberboard box; (d) plastic tray manufactured from A-PET. Drop test: Impact bruises were produced by dropping the corrugated fiberboard boxes five times from a specific dropping height onto a steel surface using a free-fall dropping tester (DTS- 5, Shinyei Technology, Japan). In this study, drop heights were 2, 3, 4 and 5 cm. Bruise measurements: Apples were left for 24 hours after being dropped, for full development of bruises. The bruise area (BA) was determined by measuring the width using a digital caliper and assuming that the bruise was elliptical 22, 24. The BA was calculated by the following equation: w w BA = π 2 4 where w is the bruise width along the major axis and w 2 is the bruise width along the minor axis. Pressure-sensitive film measurements: This study employed a two-sheet film (Fuji Film Corporation, Japan) for super low pressure. The pressure-sensitive film was placed under the apple fruits for determination of force and pressure distribution. A prescale pressure graph system (FPD-92, Fuji Film Corporation), composed of a scanner and computer, was used to evaluate the multicolor presentation of results, the resulting pressure and pressure distribution and statistical data. Statistical analysis: Statistical tests were performed using Origin software (version 6.; OriginLab Corporation, USA). Results are expressed as means ± standard deviation (SD) for each determination. Statistical analysis was done with one-way analysis of variance. Differences at p <.5 were considered to be statistically significant. Results and Discussion Apple bruising: Table shows the statistical incidence of damage and damaged areas for the apples in two commercial corrugated fiberboard boxes after being subjected to dropping impact loads. The percentage of damaged apples in the single-wall and doublewall corrugated boxes increased with the increase in drop height. As shown in Table, the damage to apples in the lower layer of both boxes was notably higher than that in the upper layer. The overall damage to apples in the double-wall corrugated fiberboard box was less than that in the single-wall corrugated fiberboard box, most likely due to the absorbed energy from the forcedeflection response of the cushioning material that was under quasi-static compression 6. The double-wall corrugated fiberboard box could thus absorb more impact energy than the single-wall corrugated fiberboard box and release less remaining energy to the apple, resulting in fewer bruises on the apples (Table ). Pressured film images: Fig. 2 shows example images of pressuresensitive films obtained after the dropping impact loads for apples in the lower layer of the single-wall corrugated fiberboard box. Significant changes in the pressured area and pressure were observed due to drop height. As expected, the pressured area increased with drop height. The total pressured areas of apples dropped from 2, 3, 4, 5 cm were 783, 376, 486, 65 mm 2, respectively. The contact pressure range was about to 2.5 MPa. () Journal of Food, Agriculture & Environment, Vol.8 (2), April 29

3 Table. Mechanical damage to apples packed in corrugated fiberboard boxes. Bruised apple percentage (%) Bruised area (mm 2 ) 3 Drop SWCFB DWCFB 2 SWCFB DWCFB height (cm) Upper Lower Upper Lower layer layer layer layer ± 9.35 a ± 4.6 a Nd ± 4.68 a ± 6.54 a ± 7.32 b Nd 4.73 ± 2.92 a ± 8.49 b 6.7 ± 4.24 c ± 6.39 a 55.2 ± 7.95 b ± 6.38 c ± d 5.3 ± 3.23 a ± 9.98 c SWCFB: single-wall corrugated fiberboard box; 2 DWCFB: double-wall corrugated fiberboard box; 3 means in the same column with different letters are significantly different (p <.5); 4 Nd: not detected. Pressure (MPa) Figure 2. Example images of pressure-sensitive films from the lower layer of the single-wall corrugated fiberboard box that had been subjected to 5 dropping impact loads from drop heights of 2 cm, 3 cm, 4 cm (c) and 5 cm (d). With pressure-sensitive film scanning, we previously showed significant changes in the contact pressure image as a result of the impact of the apple on different surfaces, depending on the drop height and number of dropping times 22, 23. However, in the case of a corrugated fiberboard box, the impact between the plastic tray and the apple is more complex than that of the simple impact on different surface materials. In this study, although some parts of the film formed a color image due to low applied pressure, in many cases, no apple damage occurred; that is, pressure below.5 MPa viewed as a green area resulted in no bruising. Apple damage was found to only occur in the deeply red region (Fig. 2), which had a defined pressured area and relative higher contact pressure level in the corrugated fiberboard box with the plastic tray. Therefore, it was not appropriate to assess and predict apple damage in such packaging using the total pressured area and average pressure. Thus, the pressured area with an average pressure above.5 MPa was determined to assess and predict apple damage. Using prescale pressure imaging and analysis software (FPS- 92-SP version 2., Fuji Film Corporation), the areas in which the pressure was below.5 MPa (green areas) were eliminated, before calculating the pressured area and average pressure. (c) (d) Pressured area and average pressure: Fig. 3 shows the pressured area (above.5 MPa) of damage to apples in both corrugated fiberboard boxes after the dropping impact loads. The pressured area of apples in the single-wall corrugated fiberboard box was greater than that in the double-wall corrugated fiberboard box. For both boxes, the pressured area increased on the pressure-sensitive film with the increase in drop height. A greater pressured area was also found for the lower layer in both boxes. Fig. 4 shows the average pressure (above.5 MPa) causing damage to apples in both boxes after the dropping impact loads. The average pressure in the single-wall corrugated fiberboard box was slightly greater than that in the double-wall corrugated fiberboard box. In the case of both boxes, no significant change in the average pressure was found as a result of drop height; the change in the average pressure between the upper and lower layers was also not significant. Bruise prediction models using the impact force obtained from pressure-sensitive film (F PSF ): As shown in Fig. 2, the change in maximum pressure scanned by the pressure-sensitive film was not significant due to drop height. The peak pressure value observed was about MPa. Thus, it was not appropriate to assess apple bruising in corrugated fiberboard boxes based on the pressured area or average pressure data alone. Fig. 5 shows the relationship between the BA and F PSF fitted to the linear regression equations for both single-wall and doublewall corrugated fiberboard boxes. F PSF was defined the product of the pressured area and the average pressure 22. A good linear relationship between the BA and F PSF was obtained for both types of boxes. The coefficients of determination (R 2 ) for single-wall and double-wall corrugated fiberboard boxes were.94 and.85, respectively. Combining the data for the two boxes, the relationship between the BA and F PSF was slightly lower (R 2 =.86) than that for the single-wall corrugated fiberboard box data alone and slightly higher than that for the double wall corrugated fiberboard box data alone. Bruise prediction models have utilized either impact energy 6, 7 or peak contact force, 5. In this study, although apple bruising could not be assessed by the pressured area, peak pressure or average pressure alone, the apple BA in the corrugated fiberboard box after the dropping impact loads was successfully assessed by F PSF. Therefore, F PSF appears to be a useful index to assess apple bruising in corrugated fiberboard boxes due to impact loads. 22 Journal of Food, Agriculture & Environment, Vol.8 (2), April

4 Pressure area (mm 2 ) Pressure area (mm 2 ) Figure 3. Pressured area of apples in the corrugated fiberboard box that had been subjected to 5 dropping impact loads: single-wall and double-wall corrugated fiberboard boxes. Average pressure (MPa) Average pressure (MPa) Figure 4. Average pressure on apples in the corrugated fiberboard box that had been subjected to 5 dropping impact loads: single-wall and double-wall corrugated fiberboard boxes. Bruised area (mm 2 ) 3 Single-wall corrugated fiberboard box box Double-wall corrugated fiberboard box box y = y.43 =.43x x RR 2 2 = F PSF (N) Figure 5. Bruise area-impact force obtained from the pressure-sensitive film (F PSF ) relationship for apple impact in two types of corrugated fiberboard boxes that had been subjected to 5 dropping impact loads. Conclusions It was demonstrated the feasibility of assessing and predicting the apple bruising that occurs in corrugated fiberboard boxes upon multiple impact loads by pressure-sensitive film technique. Significant differences in the pressure-sensitive film images were observed for apples in the corrugated fiberboard boxes. The impact force obtained from pressure-sensitive film (F PSF ) was determined to be useful for assessing and predicting apple bruising that occurs in corrugated fiberboard box packaging, with the coefficients of determination (R 2 ) for single-wall, double-wall and both corrugated fiberboard boxes of.94,.85 and.86, respectively. Future studies will focus on evaluating the bruise probability and small apple damage using this pressure-sensitive film technique. Apple bruise assessment and prediction during actual transport and handling using the pressure-sensitive film technique should also be examined. References Lewis, R., Yoxall, A., Marshall, M. B. and Canty, L. A. 8. Characterising pressure and bruising in apple fruit. Wear 26: MAFF (Ministry of Agriculture, Forestry and Fisheries). Statistics data of production and supply of fruits and vegetables in Japan. Available at: (accessed 4..) 3 Hammerle, J. R. and Mohsenin, N. N Some dynamic aspects of fruit impacting hard and soft materials. Trans. ASAE 9: Mohsenin, N. N., Jindal, V. K. and Manor, A. N Mechanics of impact of a falling fruit on a cushioned surface. Trans. ASAE 2: Chen, P. and Yazdani, R. 99. Prediction of apple bruising due to impact on different surfaces. Trans. ASAE 34: Jarimopas, B., Singh, S. P., Sayasoonthorn, S. and Singh, J. 7. Comparison of package cushioning materials to protect post-harvest impact damage to apples. Packag. Technol. Sci. 2: Lewis, R., Yoxall, A., Canty, L. A. and Romo, E. R. 7. Development of engineering design tools to help reduce apple bruising. J. Food Eng. 83: Lu, L. 8. Cushioning dropping modeling of a falling apple on the corrugated board. Trans. CSAE 24: Schoorl, D. and Holt, J. E Bruising and acceleration measurements in apple packs. Queensl. J. Agric. Anim. Sci. 3: Schoorl, D. and Holt, J. E Impact bruising in 3 apple pack arrangements. J. Agric. Eng. Res. 27: Holt, J. E., Schoorl, D. and Lucas, C. 98. Prediction of bruising in impacted multilayered apple packs. Trans. ASAE 24: Peleg, K. 98. Package product interaction in corrugated containers Journal of Food, Agriculture & Environment, Vol.8 (2), April 22

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