Postharvest: an unsung solution for food security

In agriculture, postharvest is the last stage of crop production that spans from harvesting until the produce is being utilised by consumers. It includes handling practices involving harvesting, sorting, cleaning, pre-cooling, grading, packing, storage, transportation and postharvest treatments. The moment a produce is uprooted from the ground, or separated from the parent plant, it begins to deteriorate. To totally check this deterioration process is impossible, so the only alternative we have is to slow down the progression. Only then can we retain the quality of the produce longest possible. On the other hand, food waste, which is a subset of postharvest food losses, is the loss of edible food due to human action or inaction, such as throwing away produce, not consuming available food before its expiry date or taking serving sizes beyond one’s ability to consume. The former is related to the early stages of the food supply chain (FSC) and refers to a system which needs investment in infrastructure. Food waste is applied to later stages of the FSC and generally, relates to the attitude of food suppliers and consumers. Like it or not, food losses and wastes will influence global food security. Increasing agricultural productivity is critical for ensuring global food security, but this may not be sufficient. The methods of increasing food supply include continous increase in the production area and yields as well as producing more crops per year. However, the other aspect that is always overlooked is the reduction of postharvest losses. In light of these issues, this write-up highlights some of the causes of postharvest deterioration which are identified as lack of knowledge and information, inadequate transportation facilities, unavailability of needed tools and equipment and losses at the distribution level. Pre-harvest factors are crucial for retention of quality after harvest. All related factors, such as water stress, nutrition (calcium in particular), light exposure, temperature and salinity, have a substantial influence on the postharvest quality of a produce. Quality responses to biotic and abiotic stresses are also discussed. Various strategies and interventions that have been developed and proposed, including those from UPM, to reduce postharvest losses and improve handling, storage and transportation operations of fresh produce during the entire supply chain are also highlighted. In order to control the high magnitude of postharvest losses and food waste, plausible action must be taken to upgrade the existing systems. In the present world, where millions of people go to bed without food, it would be a crime to allow continuation of postharvest losses and food wastes

Growth, flowering and cut flower quality of spray chrysanthemum (Chrysanthemum morifolium Ramat) cv. V720 at different planting densities

Growth, flowering and flower quality of spray chrysanthemum (Chrysanthemum morifolium Ramat) cv. V720 planted at densities of 44, 56, 70, 83 and 104 plants/m2 were evaluated. Stem diameter, leaf number, total leaf area, and overall plant fresh weight were reduced by 16, 7, 36 and 25%, respectively, but the leaf area index was increased by 50% at the highest planting density (104 plants/m2) as compared to the lowest density (44 plants/m2). Time taken to showing colour and harvesting, which was calculated from the beginning of short day, was delayed by high planting density. Measurement on the spray diameter showed a clear reduction at 83 plants/m2, and this improved the spray form. The length of flower stalks and vase life were not affected. There was marked reduction in the number of flower stalks as well as flower number at high densities (83 and 104 plants/m2). Generally, the cultivar (V720) used in this study can be planted at high density (83 plants/m2) under lowland condition and able to produce the premium grade flowers

Defoliation of chrysanthemum (Chrysanthemum morifolium Ramat) cv. Reagan Sunny for improved flowering and cut flower quality

The effects of different levels of defoliation i.e. 0 (control), 20, 40, 60 and 80% at visible floral bud stage on growth, flowering and cut flower quality of chrysanthemum (Chrysanthemum morifolium) cv. Reagan Sunny were investigated. Plant height was only reduced by 5% at the highest level of defoliation, whereas the stem diameter was not affected. The time of floral bud break (showing colour), was delayed as level of defoliation increased. However, time of floral bud break within a plant was more synchronised. The spray diameter was reduced and vase life was increased by defoliation up to 60%. Both contributed to better cut flower quality. Other quality parameters such as flower size and stem diameter were not markedly affected. Total fresh and dry weights were linearly decreased with level of defoliation. There was a change in dry matter distribution, in which more dry matter was partitioned to the structural parts i.e. the stems and flower stalks as level of defoliation increased. There was no change on dry matter partitioning to flowers by defoliation. Defoliation at 60% can be the compromised level for cv. Reagan Sunny grown under high temperature environment

Effects of pre-harvest production practices on post-harvest water loss of Leeks and Pak Choi.

The utilization of pre-harvest conditions as crop management tools to control post-harvest weight (water) loss had been studied. Studies on two model crops i.e. leek and pak choi had shown some promising uses of these production conditions in regulating weight loss from harvested leafy vegetable. Pre-harvest conditions such as environmental (temperature and light) and cultural (mineral nutrition, density of planting, salinity and irrigation) had been investigated. Water retention during storage was improved in pseudostems from leeks grown with adequate water supply, high light level, lower temperatures and K supplement in the growing media. Pseudostems from salinized plants conserved more water than non-salinized plants and leeks grown at 35 plants m־² retained water better than the other three plant densities (17.5, 22 and 44 plants mm־²). There were significant (p<0.001) interactions between temperature, salinity and water stress and cultivars on water loss from shoots of pak choi with shoots produced at 25°C, moderate salinity and water stressed being more resistant to water loss

Model Comparisons for Assessment of NPK Requirement of Upland Rice for Maximum Yield

Upland rice farmers in Malaysia still depend on resultant ash from burning for K and N sources. Efficient use of chemical fertilizers in upland rice needs accurate assessment of required nutrient elements. The present study was performed to determine the N, P, and K requirements of three upland rice varieties grown on idle land (Bukit Tuku soil, AQUIC KANDIUDULT) using four response models. A glasshouse experiment was conducted using 0-200 kg N ha-1 (urea, 46%N), 0-120 kg P2O5 ha-1 (TSP, 45% P2O5), and 0-150 kg K2O ha-1 (MOP, 60% K2O), each at five levels. Three upland rice varieties used in the experiment were Ageh, Kendinga and Strao. The grain yield (14% moisture content) was measured at harvest and fitted using linear (L), linear with plateau (LP), quadratic (Q), and quadratic with plateau (QP) response models. The QP proved itself as the best fitted response model for the determination of fertilizer recommendation rates for maximum yield of upland rice cultivars used. The fertilizer rates were 112 kg N ha-1, 78 kg P2O5 ha-1 and 158 kg K2O ha-1 for Ageh (QP); 138 kg N ha-1 (LP), 87 kg P2O5 ha-1 (QR), 119 kg K2O ha-1 (QP) for Kendinga; and 125 kg N ha-1 (Q), 85 kg P2O5 ha-1 (LP) and 127 kg K2O ha-1 (L) for Strao

Postharvest characteristics of two flowering stages of torch ginger (Etlingera elatior) inflorescences

Torch ginger (Etlingera elatior), a flourish in tropical and subtropical climates crop, with extravagant and showy inflorescence may be used as cut flower at each developmental stage. Limited studies have been undertaken to reveal the postharvest performance of this leafless inflorescence, especially at advanced developmental stages. Therefore, the objective of this study was to elucidate the postharvest performance of the torch ginger inflorescence treated with different vase solutions. Inflorescences at two flowering stages i.e., tight bud stage and torch shows stage at about 35 and 58 days, respectively, after emergence from rhizome, were used in this study. Sucrose (20 g L-1), 8-hydroxyquinoline sulfate (8-HQS, 0.1 g L-1) and distilled water were used as vase solution treatment. Postharvest characteristics, including vase life, relative fresh weight (RFW), dry weight, solution uptake rate, respiration and ethylene production rate were evaluated. Results showed that vase life of tight bud stage inflorescence was significantly higher than torch shows stage irrespective of treatments used. In contrast, significantly higher solution uptake rate was shown in the torch shows stage inflorescence. There was no significant difference in dry weight and respiration rate measured. No ethylene was detected in all treated inflorescences throughout the study. Prolongation of vase life was associated with the increase in RFW. Increase of RFW was found in tight bud stage inflorescence but reduction of RFW was shown in torch stage inflorescence at the end of vase life. The decrease of RFW could be due to the breakdown of stored carbohydrates in peduncle for the development of true flowers for pollination purpose. Supplementation of sucrose promoted the opening of true flowers. The use of 8-HQS and distilled water enabled the development of true flowers, but they failed to open. Sucrose treated inflorescences both in tight bud and torch stage showed better postharvest quality compared to 8-HQS and distilled water

Cell Wall Enzymes Activities and Quality of Calcium Treated Fresh-cut Red Flesh Dragon Fruit (Hylocereus polyrhizus)

This study was aimed at evaluating the effect of post-cut application of CaCl2 on activity of polygalacturonase (PG) and pectin methylesterase (PME) and quality of fresh-cut dragon fruit (Hylocereus polyrhizus). Fruit slices were prepared from fully matured fruits before being dipped into three levels of calcium concentration (CaCl2: 0, 2.5 & 7.5 g L-1) at four durations of dipping (0, 4, 8 & 12 min). The activities of PG and PME enzymes of fruits extract were lower when treated with high concentration of CaCl2 for a longer duration of dipping. The Ca treatment did not cause any marked effects on colour, pH, titratable acidity and ascorbic acid content. Soluble solids content and Ca content in cut fruit were affected by duration of dipping. The firmness of fruit slices treated at the highest CaCl2 concentration (7.5 g L-1) increased at the beginning of the treatment but reduced as the durations of dipping were extended to 8 and 12 min. Lack of a linear increase in tissue firmness of fresh-cut dragon fruit in response to high concentrations of CaCl2 post-cut application showed that treatment should be administered with a great care to appropriate concentration of CaCl2 duration of exposure are applied

Gas exchange characteristics and Leaf Chlorophyll content of two local hosts infected by Jarum Mas (Striga asiatica).

The effect of Jarum Mas (Striga asiatica), a parasite, on the gas exchange capacity and leaf chlorophyll content of two local grasses was studied. Infection by S. asiatica reduced the host photosynthetic capacity by reducing the apparenl quantum yield used for CO, fixation. In Ischaemum indicum, lower photosynthesis rates were also due to the reduction of RuBP-carboxylase capacity and the RuBP-carboxylase regeneration capacity of the host

The Exploitation of Root-sourced Signals to Reduce Irrigation and to Regulate Leaf Growth of Pepper Plants Capsicum annuum L.

The effect of partial root drying (PRD) on growth and physiological responses of pepper plants Capsicum annuum L. cultivar MC12 was investigated under high temperatures and a humid tropical climate. The leaf water potential, photosynthetic rate, stomatal conductance and transpiration rate of Capsicum plants grown under PRD over a period of 10 days were lower than those grown under well watered conditions. Removal of the droughted roots resulted in resumption of all leaf gas exchange parameters confirming the presence of signals coming directly from the droughted roots. Leaf growth rate was negatively affected by PRD techniques; as a consequence leaf area per plant was reduced. Total fruit yield ofPRD plants was about 73% of the control plants' fruit yield while the amount of water added to the PRD plants was half the quantity added to the controls