Postharvest Losses and Storage of Cereals (PDF)

Question 1: How can we reduce post-harvest losses during the storage of cereals? - Controlling moisture, air movement + Reduction of moisture content to a safe level (usually around 12-14%) and cooling of the grain to prevent mold growth and pest infestation....

Question 1: How can we reduce post-harvest losses during the storage of cereals? - Controlling moisture, air movement + Reduction of moisture content to a safe level (usually around 12-14%) and cooling of the grain to prevent mold growth and pest infestation. + Modification of atmospheric condition - Preventing attacks of microorganisms, insects, and rodents. - Controlling temperature and moisture + Temperature is a critical factor for storage up to certain limits + Moisture: High moisture content favors biochemical and chemical changes in the grain as well as the growth of microorganisms, insects, and mites during storage Question 2: Why is temperature very critical during storage? - Because it directly influences the quality, safety, and self-life of the produced: + Cooler storage temperatures generally extend the shelf life of products by slowing down metabolic and chemical processes that lead to deterioration. + Keeping the temperature low inhibits the activity of pests (insects, mites, and weevils) and microbial growth, ensuring the safety and longevity of stored materials. + Optimal temperature helps to preserve aroma and flavors in produce by minimizing chemical changes because volatile compounds (e.g., essential oils) are sensitive to heat and can evaporate at high temperatures. + Temperature affects the moisture content of stored products. Higher temperatures can cause moisture migration, leading to condensation and localized wet spots, which can further spoil the products. Question 3: What is the best way to preserve species? - Ground and dried herbs and species need to be stored in a cool dark area that is free from humidity.  - Humidity and moisture, heat, and direct sunlight can all degrade the pungency of herbs and species. - Always keep species in an airtight container that is out of direct sunlight, preferably in a cool dark cupboard. - The temperature of the storage device should be kept stable at below 20° C. - Fluctuations will eventually result in condensation which causes mold to form. Question 4: What are the different types of tea? - All true teas originate from the leaves of the Camellia sinensis plan: + Black tea: Fully oxidized, giving it a strong flavor and dark color. + Green tea: Unoxidized, retaining a green color and a more delicate flavor. + Oolong tea: Partially oxidized, offering a balance between black and green tea + White tea: Minimally processed, with a light, subtle flavor. + Yellow tea: - Herbal tea: doesn't come from tea leaves. It's made from dried herbs, fruits, and flowers Question 5: How to store pulses safely? - Store dried pulses in a cool, dark, and dry place. - Store pulses in airtight containers such as a mylar bag or a glass jar to protect them from air, moisture, and pests. - Store dried in the freezer inside a freezer bag or airtight container for long-term storage. Freezing will kill any insects and prevent spoilage. The dried pulse will last indefinitely in the freezer. - Add oxygen absorbers into the container. Oxygen absorbers contain iron and remove oxygen from their surroundings, killing bugs. - Vacuum seal pulse to remove any excess oxygen. Question 6: How do you cut flowers last longer? - Recruiting the stem at an angle increases the surface area for water absorption and eliminates air from the conducting vessels which increases the rehydration rate.  - Cut stem exuding milky fluid must be treated with hot water dip for a few seconds because milky fluid can cause stem plugging. - Use standard holding or vase solution to provide nutrients, reduce bacteria, and help flowers stay fresh longer. - Remove leaves below the water line because it can promote bacteria growth, which clogs the stems and reduces water uptake. - Change the water regularly to keep it clean and prevent bacteria buildup. - Use clean tools and vase Question 7: How does Postharvest Technology stimulate agricultural production? - Prevent post-harvest losses - Improves nutrition - Add value to agricultural products - Opens new marketing opportunities - Generates new jobs Question 8: How can the deterioration in grain be assessed? - Changes in grain color, - Sour or musty smell - Loss of viability - Fat acidity increase - Glutamic acid decarboxylase activity decreases Question 9: What is required for a good storage system? - Protect common storage loss agents such as insect pests, rodents, molds, birds, and man. - Maintain an even, cool, and dry storage environment. The maize should be placed on pellets above the floor to avoid cold conditions that may lead to molds. - Should not allow re-wetting of grain by either moisture migration or rain. - Offer reasonable protection from thieves, nature vagaries or any other factor of physical damage - Allow aeration as it helps in keeping down the relative humidity of interstitial gases - Proper sanitization and fumigation to prevent the growth of pathogens Question 10: What are the Purposes of storage? - Slow down biological activity - Reduce product drying and moisture loss - Reduce pathogenic infection - Avoid physiological disorders - Reduce physical damage Question 11: Reasons for postharvest losses Question 12: Cite some factors affecting the Postharvest life of Flowers - Pre-harvest: + Genetic or inherent makeup + Growing conditions § Light § Temperature § Humidity § Water § Nutrients § Pest and diseases § Toxic gases - Harvest + Stage of harvest + Time of harvest + Method of harvest - Post-harvest + Temperature + Light + Humidity + Water quality + Ethylene + Preservatives + Ventilation + Packaging + Diseases and Pests Question 13: What is the advantage of pulsing - Prolongs vase life of water - Promotes opening of buds - Remains the colors of the flower Question 14: Factors influencing deteriorative changes during storage - Physical: temperature and humidity - Chemical: moisture, oxygen, and oxidation - Physiological: respiration, heating - Biological: insects, microorganisms, mites, rodents, and birds. - Changes occurring during storage: CHO, Protein, Fat, Mineral, discoloration, viability, and Flavor. Question 15: Cite changes occurring during storage. Question 16: Purposes of cereal storage - Retain the supply of the food grain throughout the year - Retain the viability of the seed for planting in the following season. - Take advantage of higher prices by the traders - Serve as a reserve during the time scarcity.