Environmental Factors Affecting Postharvest PDF

Environmental Factors Affecting Postharvest Subject: Hort607 Prepared by: Ana Liza D. Latinang  TOPICAL OUTLINE POSTHARVEST DEFINITION ENVIRONMENTAL FACTORS AFFECTING POSTHARVEST TEMPERATURE RELATIVE HUMIDITY ATMOSPHERIC CONDITION LIGHT O...

Environmental Factors Affecting Postharvest Subject: Hort607 Prepared by: Ana Liza D. Latinang  TOPICAL OUTLINE POSTHARVEST DEFINITION ENVIRONMENTAL FACTORS AFFECTING POSTHARVEST TEMPERATURE RELATIVE HUMIDITY ATMOSPHERIC CONDITION LIGHT ONLINE REFERENCE  SHORT REVIEW What is Postharvest? Post-harvest is a system of handling, storing, and transporting agricultural commodities after harvest.  ENVIRONMENTAL FACTORS AFFECTING POSTHARVEST 1. TEMPERATURE 2. RELATIVE HUMIDITY 3. ATMOSPHERIC CONDITION 4. LIGHT  1. TEMPERATURE Temperature is one of the most crucial environmental factors that affect the Postharvest life of the stored product.  1.A HIGH TEMPERATURE It Increases transpiration rate, thus increasing water loss. High temperatures can limit the development of color and ripening in some fruit vegetables. Short periods of high temperatures can benefit long storing root and bulb crops by increasing wound healing.  1.A HIGH TEMPERATURE Temperatures over 30°C can destroy the enzymes in vegetables that are responsible for color changes and maturation. For example, tomatoes held at over 30°C may fail to develop normal red color.  1.A HIGH TEMPERATURE High temperatures can stimulate the breakdown of chlorophyll, resulting in premature yellowing, and cause rapid softening, wilting, and dehydration.  1.B LOW TEMPERATURE Reducing the temperature gradually after harvest can effectively acclimatize the vegetable to low temperatures. For example, one day at 18°C or two days at 10°C both delayed the appearance of chilling injury in zucchini stored at 5°C.  1.B LOW TEMPERATURE Fresh (left) and frozen carrots and lettuce, showing the dehydration and water- soaking symptoms that are typical of freezing injury.  1.B LOW TEMPERATURE Mature red capsicums are less susceptible to chilling injury than green fruit. The photo shows the effect of storage for 3 weeks at 0°C, 2°C, 4°C or 6°C on capsicum quality. Green fruit at 0°C and 2°C are showing light pitting, an early symptom of chilling damage.  1.B LOW TEMPERATURE -The undesirable temperature in storage conditions may cause chilling and freezing injury, heat injury which drastically affects the quality of postharvest produce.  2. RELATIVE HUMIDITY The rate of loss of water from fruit, vegetables, and flowers depends upon the vapor pressure deficit between the surrounding ambient air, which is influenced by temperature and relative humidity.  2. RELATIVE HUMIDITY The rate of deterioration is a combined factor of temperature and relative humidity and affects the product in the following manner: Low Temperature & High Relative Humidity -- Low deterioration Low Temperature & Low Relative Humidity -- Moderate deterioration High Temperature & High Relative Humidity -- High deterioration High Temperature & Low Humidity -- Very high deterioration  3. ATMOSPHERIC CONDITION Build up of undesirably high carbon dioxide and very low levels of oxygen in the storage facility can lead to many physiological disorders leading to spoilage.  3. ATMOSPHERIC CONDITION Eg. Hollow heart disease in potatoes is due to faulty oxygen balance in storage or during transportation. Exposure of fresh fruits and vegetables to O2 levels below the tolerance limits or to CO2 levels above their tolerance limits in storage rooms may increase anaerobic respiration and the consequent accumulation of ethanol and acetaldehyde, causing off-flavors.  3. ATMOSPHERIC CONDITION The other bad effects of unfavourable gas composition include irregular ripening of certain fruits, soft texture, lack of characteristic aroma, poor skin color development, etc. Example: Controlled Atmosphere (CA) storage of Apples(0-10C with 1- 2%CO2 and 2-3%O2, RH 90-95%) for 6-12 month.  4. LIGHT Similarly, light has a significant impact on the color indices of fruits and vegetables, which regulate their shelf life. The development of color in fruits after harvest is related to the accumulation of various pigments such as lycopene, chlorophyll, or anthocyanin.  4. LIGHT Exposure of potatoes to light results in the greening of the tuber due to the formation of chlorophyll and solanine which is toxic to humans on consumption.  ONLINE REFERENCE https://link.springer.com/article/10.1007/s11947-020-02534- 6#:~:text=Similarly%2C%20light%20has%20a%20significant,2011%3B%20Xu%20et%20al http://ecoursesonline.iasri.res.in/mod/page/view.php?id=16327#1 https://www.nature.com/articles/s41598-019-38877-0 THANK YOU!