Effects of Vibration Stress on the Quality of Packaged Apples during Simulated Transport

Abstract

Purpose: The characteristics of in-transit vibration stress and possible damage to packaged apples were examined. Methods: A simulated transportation environment with a specific power density profile was used for vibration impact experiments to determine the resulting decrease in packaged apple quality. Apples with or without vibration stress were stored at low temperature (<TEX>$5{\pm}0.8^{\circ}C$</TEX>, 75-85% relative humidity) for 30 days. Statistically significant differences (p <TEX>${\leq}$</TEX> 0.05) were found between apples with and without vibration stress for concentration of oxygen (<TEX>$O_2$</TEX>; 11.2% and 14.1%, respectively; initially <TEX>$29{\pm}0.4%$</TEX>), carbon dioxide (<TEX>$CO_2$</TEX>; 26.4% and 21.8%; initially <TEX>$1{\pm}0.2%$</TEX>), and ethylene (79.4 <TEX>${\mu}LL^{-1}$</TEX> and 55.6 <TEX>${\mu}LL^{-1}$</TEX>; initially <TEX>$14.1{\pm}0.6{\mu}LL^{-1}$</TEX>) in the headspace of a gas-collecting container after 30 days of storage. Results: Significant differences were also measured for apples with and without vibration stress with respect to soluble solid content (15.4% and 14.9%, respectively; initially <TEX>$12.9{\pm}0.8%$</TEX> and <TEX>$13.1{\pm}1.1%$</TEX>), weight loss (10.1% and 8.2%), and firmness (139.7 kPa and 163.3 kPa; initially <TEX>$213.8{\pm}6.2$</TEX> kPa and <TEX>$209.1{\pm}7.9$</TEX> kPa) after 30 days of storage. Conclusions: The vibration stress clearly accelerated the degradation of apple quality during storage, resulting in increased weight loss, soluble solid content, and headspace <TEX>$CO_2$</TEX> and ethylene production, and decreased firmness and headspace <TEX>$O_2$</TEX>.