Some storages have limited control over their internal environment and undergo daily and seasonal fluctuations in both temperature and humidity, which cause variation in the metabolic activity of stored products. As a result, it is difficult to assess and compare the performance of these imperfect storages using measures of environmental control. We propose using measures of plant senescence as a proxy for estimating storage performance of these “imperfect” storages based on the premise that physiological processes integrate changes of temperature and/or humidity in a predictable, mathematically describable manner. We evaluated amaranth (Amaranthus tricolor L.) as a model plant for evaluating imperfect storages using a red-leaf cultivar Pusa lal chaulai and a green-leaf cultivar Pusa kiran. Amaranth is a leafy vegetable grown worldwide and is a highly nutritious and versatile food. Cumulative respiration, a measure of integrated metabolic activity, was regressed against leaf abscission, chlorophyll loss, and leaf yellowing of amaranth stems for four storages having different, variable, temperature profiles. Storages included 1) an evaporatively cooled (EC) structure; 2) a solar-refrigerated and evaporatively cooled (SREC) structure; 3) an uncooled laboratory (UL); and 4) a household refrigerator (REF). We found that the rate of abscission, chlorophyll loss, and leaf yellowing differed markedly for the four storages; however, these measures of senescence were linearly related to estimates of cumulative respiration. The ease of measuring leaf abscission, chlorophyll loss, and leaf yellowing permits data collection even with minimal resources. We propose that amaranth would make an effective model plant for comparing the performance of storages differing dramatically in temperature control. A 10% leaf abscission in amaranth is proposed as a target for comparing storages.

Adequate cold storage facility for Horticultural products is critical due to their perishable nature. Green energy based evaporative cooling storage unit is a sustainable and efficient solution for small scale farmers and vegetable vendors in hot and dry climates who need to store their produce. Solar power operated evaporative cooling structures are low cost and efficient in reducing ambient temperature and increasing relative humidity, which increases the shelf-life of vegetables. A green energy-based evaporative cooling transit storage unit of 0.63m3 capacity was designed and fabricated. The transit unit was designed and operated as a a tricycle. Two suction fans (15.6W), submersible water pump (12W) and LED light (2.88Wp) were powered through two 100-Wp solar panels. Two batteries, 7Ah each were also used to store energy. The storage unit was made up of MS sheets of 1.2mm thick while a side of the system was made up of GI wire mesh with honeycomb pad. To test the performance of the developed unit tomato, spinach and radish were used. Results revealed that there was a significant difference (P=0.05) in PLW, firmness, TSS, and colour values of the vegetables when stored inside the unit compared to vegetables stored in ambient condition. The ambient temperature during the study was 32.2-43.4°C and RH was 21.1- 46%. The drop-in temperature was 7.8 to 14.8°C as compared to ambient conditions, while RH in the cooling chamber increased considerably to 84%.  The average cooling efficiency obtained was 84.12%.  The shelf life of stored vegetables inside the unit was 2-5 days higher than those kept under ambient conditions.

India is the second-largest producer of vegetables. However, vegetables are critical for storage, due to their highly perishable nature, lack of cold storage and transportation facilities. Vegetables get shrivel, whither rapidly, especially under hot conditions, if not preserved just after harvest. The study was conducted at ICAR-IARI to access the effect of abiotic parameters on vegetable quality with time. Effect of abiotic parameters on vegetable storability was studied and statistical analysed results revealed that there was a significant difference (P=0.05) in storage parameters occur when vegetables stored at different temperature and relative humidity. Storability parameters physiological loss in weight (PLW), firmness, colour values and total soluble solids (TSS) of vegetables tomato, spinach, and radish with different temperature and relative humidity were determined. The effect of abiotic parameter i.e. temperature and relative humidity on PLW physiological loss in weight was found significantly different at 5% level of significance. Temperature reduction of  5 – 10°C  and RH increment of 10% have a significant effect on quality parameters i.e. PLW, TSS, colour values of vegetables PLW of vegetables and TSS showed an increasing trend with an increase in temperature and decrease in relative humidity. The firmness of tomato and radish showed a decreasing trend with the increase in temperature and decrease in relative humidity but spinach firmness trend was found the opposite. Thus control over these abiotic parameters is essential to retain the quality of the vegetables and prevent their spoilage.