Studies On Preservation Of Harvested Bamboo Shoot And Change In Quality Of Soft Package Shoot During Storage At Lower Temperature

Fistly, bamboo shoots (Dendrocalamopsis oldhami) were dipped in5mmol/L oxalic acid solution for10min, and then stored at low temperature (4℃). The physiological effects of oxalic acid on bamboo shoots in relation to fresh-keeping, such as browning control and lignification retard, were investigated.. Secondly, bamboo shoots (phyllostachy Praecox f. preveynalis) were dipped in5mmol/L oxalic acid solution, or1mg/L ozone, or5mmol/L oxalic acid+1mg/L ozone for10min, and then stored at low temperature (4℃). The synergistic effects of oxalic acid in combination with ozone on bamboo shoots were also investigated. Thirdly, to find a fast detection method for measuring fresh-level of bamboo shoot, a correlation model among texture characteristics, chromatic aberration, and moisture content to near-infrared spectra was established. Finally, advanced processing technology for producing soft package bamboo shoots and change in quality of this produce were studied during storage at low-temperature for12months. The results were shown as follow:1. As compared to control, oxalic acid treatment decreased activities of PAL, PPO, POD and LOX, and increased activities of SOD and CAT, and significantly decreased hydrogen peroxide content, and also inhibited browning on the wound surface of bamboo shoots. In addition, the increasing rate of lignin, cellulose and firmness in bamboo shoots treated with oxalic acid were apparently lower than that of in control. These data suggested that oxalic acid could inhibit browning and lignification in bamboo shoots, and in turn might contribute to maintaining better quality of bamboo shoots during storage at lower temperture.2. As compared to control, oxalic acid+ozone treatment inhibited respiration rate, decreased activities of PAL, PPO and LOX, increased SOD and CAT activity, significantly decreased hydrogen peroxide content. In addition, the increasing rate of MDA, firmness, and electrolyte in bamboo shoots treated with oxalic acid+ozone were apparently lower than that of in control, and the efficiency was better than that of with oxalic acid or ozone alone. These data suggested that oxalic acid+ozone treatment could delay ripening and lignification in bamboo shoots by a synergistic effect.3. A correlation model between texture characteristics and near-infrared spectra was established. The results of validation showed that the model was good fitness, and could reflect a perfect relationship among texture characteristics, chromatic aberration and moisture content to near-infrared spectra. Thus, a nondestructive testing with near-infrared spectra for measuring fresh level of bamboo shoot was possible.4. K, Na and the other elements in soft package bamboo shoot gradually transported to the liquid, and contents of amino acid and total sugar in bamboo shoots decreaed, and transmissivity and pH in liquid also declined during storage. These data showed that change in quality of bamboo shoot with soft packed decreased slowly during storage at lower temperature for12months, and the produce still maintained good quality for consumption.