Study on quality preservation of fresh agricultural products under controlled atmosphere conditions.

本研究探讨了贮藏过程中控制大气条件对新鲜香菇、草莓、芦笋等农产品品质保鲜的影响。在贮藏过程中，将O_2浓度降低到1%和（或）将CO_2浓度提高到20%，会使鲜香菇的呼吸速率比正常空气更低。较低的O_2浓度和较高的CO_2浓度均降低呼吸速率。PPO活性，即在褐变反应中具有活性的酶，在正常空气中增加，但在储存期间的气体处理中降低。增加CO_2浓度对鲜香菇PPO活性的影响大于降低O_2浓度。综合评价，10%和5% O_22 + 20% CO_2的CA处理能较好地保存鲜香菇的品质。草莓可以耐受高浓度的二氧化碳，即二氧化碳浓度越高，草莓的呼吸速率越低，从而延长了草莓的保质期。在极低的1%的二氧化碳和/或极高的20%的二氧化碳中保持更多的草莓会导致呼吸速率降低。高浓度CO2导致呼吸当量（RQ）不等于1，这意味着发生了无氧呼吸。在贮藏过程中，较高的CO_2浓度阻碍了l -抗坏血酸含量的降低。草莓可以承受20%的二氧化碳，对真菌感染有有效的预防作用。在贮藏过程中，降低氧对芦笋茎呼吸速率的影响大于增加CO_2处理。CO_2浓度越高，O_2浓度越高，出现尖端伸长率越低。在CA条件下贮藏的芦笋比在正常空气条件下贮藏的芦笋更能减少叶绿素的降解。低O_2和/或高CO_2处理也减少了正常灰绿色的变浅和变黄。低O_2和/或高CO_2处理比在正常空气中多保存蔗糖的百分比达20天。总体而言，贮藏5 d后，芦笋中l -抗坏血酸含量急剧下降。不同产物的呼吸行为预测与Arrhenius和Gore方程吻合较好，高温依赖性降低了温度变化对呼吸速率的影响。Q_<10>的产品通常在低温时值较高，在高温时值较低。本研究建立的测量系统在测量农产品中呼吸速率，特别是在封闭系统中，其准确性得到了很好的验证。此外，这些系统的数据将有利于设计CA和/或MA在现在和将来的采后处理。少

This research discusses the effects of controlled atmospheric conditipns during storage for quality preservation of fresh shiitake, strawberries, asparagus and other agricultural products.Decreasing O_2 concentration to 1% and/or increasing CO_2 to 20% during storage will reduce the respiration rate of fresh shiitake more than normal air. Both the lower O_2 concentration and the higher CO_2 concentration lower the respiration rates. PPO activity, the enzyme active in the browning reaction, increase in normal air but decreases in gas treatment during storage. Increasing the CO_2 concentration has a greater effect on the PPO activity in fresh shiitake than decreasing the O_2. From a total assessment, the CA conditions in 10% and 5% O_22 with 20% CO_2 could preserve the quality of fresh shiitake better than other treatments.Strawberries are found to tolerate high CO_2 concentrations, that is the higher the CO_2 atmospheres reduces the respiration rate, hence extends the shelf life. Keepin … More g strawberry in a very low 1% O_2 and/or a very high 20% CO_2 causes a reduced respiration rate. The high CO2 concentration causes a respiratory quatient (RQ) is not equal to 1 which means that anaerobic respiration has occured. The high CO_2 concentration prevents the reduction pf L-ascorbic acid content during storage. Strawberries can tolerate 20% CO_2 and that is effective for preventing fungal infection.Decreasing oxygen has a greater efect on reducing respiration rate of asparagus spears during storage than treatment with increasing CO_2. The higher the CO_2 concentration in combination with 10% O_2 the lower the occurrence tip elongation. Asparagus spears stored under CA conditions can reduce chlorophyll degradation more than those stored in normal air. Treatments in low O_2 and/or high CO_2 also reduce the lightening and yellowing of the normal gray-green color. Low O_2 and/or high CO_2 treatments preserve the percentage of sucrose up to 20 days longer than thpse in normal air. In overall data, the L-ascorbic acid content in asparagus spears drastically decreased in 5 days of storage.The prediction of the respiratory behavior of the various products fitted very well with the Arrhenius and Gore equations The high temperature dependence decreases the effect of temperature change on respiration rate. The Q_<10> of products commonly present a higher value in low temperature and a lower value in higher temperature.The measurement system established in this study has been well verified in its accuracy in measuring the respiration rate in agricultural products, especially in closed system. Moreover, the data from these system will be advantageous in designing CA and/or MA in present and future postharvest handling. Less