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This is the complete lecture note for CPS 408 Post Harvest Physiology and Produce Storage. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: CPS 408 Course title: Post Harvest Physiology and Produce Storage Course credit load: 2 Units Series 1: Storage Life of Harvested Fruits, Seeds, Vegetables, and Flowers Part 1.1: Post-harvest physiology of crop produce Sub-Part 1.1.1: Nature of harvested produce as living entities Sub-Part 1.1.2: Physiological changes after harvest Sub-Part 1.1.3: Factors influencing storage life Part 1.2: Storage life of fruits and vegetables Sub-Part 1.2.1: Characteristics of fruits and vegetables affecting storage Sub-Part 1.2.2: Common storage problems in fruits and vegetables Sub-Part 1.2.3: Strategies to extend storage life Part 1.3: Storage life of seeds and flowers Sub-Part 1.3.1: Seed viability and dormancy in storage Sub-Part 1.3.2: Storage behaviour of ornamental flowers Sub-Part 1.3.3: Preservation techniques for seeds and flowers Part 1.4: Traditional and modern storage practices Sub-Part 1.4.1: Traditional methods of storage and preservation Sub-Part 1.4.2: Modern approaches to prolonging storage life Sub-Part 1.4.3: Comparative evaluation of traditional and modern practices Introduction
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Freshly harvested fruits, seeds, vegetables, and flowers may appear lifeless once removed from the field, yet they remain living entities that continue to respire, age, and respond to their environment. Their storage life is therefore limited, and without proper handling, significant losses can occur. Understanding how these products behave after harvest is essential for preserving quality, reducing waste, and ensuring that consumers receive produce in good condition. This Series sets the foundation for appreciating the delicate balance between physiology and storage practices. The aim of this Series is to equip you with the knowledge and skills to explain the post-harvest physiology of crop produce, analyse the factors influencing storage life, and evaluate both traditional and modern methods of preservation. We shall commence this Series by examining the post-harvest physiology of crop produce, focusing on their nature as living entities and the changes they undergo after harvest. Next, we will explore the storage life of fruits and vegetables, considering their unique characteristics, common problems, and strategies to extend their shelf life. Following that, we will move on to the storage behaviour of seeds and flowers, highlighting issues of viability, dormancy, and preservation techniques. Finally, we will wrap up by comparing traditional and modern storage practices, assessing their effectiveness and relevance in maintaining the quality of harvested produce. Series Learning Outcomes Upon completing this Series, you should be able to: SLO 1.1 define post-harvest physiology and explain the nature of harvested produce as living entities, SLO 1.2 describe the physiological changes that occur after harvest and analyse the factors influencing storage life, SLO 1.3 explain the characteristics of fruits and vegetables that affect their storage life, SLO 1.4 identify common storage problems in fruits and vegetables, SLO 1.5 demonstrate strategies for extending the storage life of fruits and vegetables, SLO 1.6 describe seed viability and dormancy in relation to storage, SLO 1.7 explain the storage behaviour of ornamental flowers, SLO 1.8 evaluate preservation techniques used for seeds and flowers, SLO 1.9 describe traditional methods of storage and preservation, SLO 1.10 explain modern approaches to prolonging storage life, and
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS SLO 1.11 compare traditional and modern storage practices in terms of effectiveness and relevance. 1.1 Post Harvest Physiology of Crop Produce 1.1.1 Nature of harvested produce as living entities Harvested produce such as fruits, seeds, vegetables, and flowers remain living entities, meaning they continue to respire, metabolise, and undergo physiological changes even after being detached from the parent plant. Their cells remain active, and processes such as respiration and transpiration persist, influencing storage life. Recognising produce as living systems helps us understand why they deteriorate over time and why careful handling is essential. Fill in the blank: Harvested produce continues to __________ even after being removed from the parent plant. Plate 1.1 Harvested produce as living entities
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.1.2 Physiological changes after harvest After harvest, produce undergoes several physiological changes, including respiration, transpiration, and senescence. Respiration is the process by which stored carbohydrates are broken down to release energy, while transpiration refers to the loss of water vapour from produce surfaces. Senescence is the natural ageing process that leads to deterioration in quality. These changes reduce storage life and must be managed through appropriate storage conditions. Fill in the blank: The natural ageing process that leads to deterioration in quality is called __________. Figure 1.1 Physiological changes after harvest 1.1.3 Factors influencing storage life The storage life of produce is influenced by both internal and external factors. Internal factors include the type of produce, its maturity at harvest, and inherent biochemical composition. External factors include temperature, humidity, handling practices, and exposure to light or gases. For example, fruits harvested at full ripeness have shorter storage life compared to those harvested at mature but unripe stages. Proper management of these factors is critical to prolonging shelf life and reducing losses.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Fill in the blank: Fruits harvested at full __________ generally have shorter storage life than those harvested earlier. Factor Type Examples / Notes Internal factors Genetic makeup, respiration rate, moisture content, and maturity stage at harvest. Produce harvested immature or overripe has shorter storage life. External factors Temperature, relative humidity, light exposure, and handling practices during storage and transport. Poor handling increases mechanical damage and spoilage. Biological factors Presence of pests, diseases, and microbial contamination that accelerate deterioration. Packaging and storage conditions Use of ventilated crates, controlled atmosphere storage, and proper sanitation extend shelf life. Box 1.1 Factors influencing storage life of harvested produce Pilot questions 1.1 Define post-harvest physiology. State one reason why harvested produce is considered a living entity. Mention one physiological change that occurs after harvest. What is senescence? Give one external factor that influences storage life. 1.2 Storage Life of Fruits and Vegetables 1.2.1 Characteristics of fruits and vegetables affecting storage Fruits and vegetables are highly perishable because they contain high amounts of water and remain metabolically active after harvest. Their storage life depends on factors such as maturity stage, respiration rate, and sensitivity to environmental conditions. For example, climacteric fruits like bananas and mangoes continue to ripen after harvest, while non-climacteric fruits such as grapes and citrus do not. Vegetables, particularly leafy types, lose water quickly and wilt if not stored under cool and humid conditions.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Fill in the blank: Fruits such as bananas and mangoes are classified as __________ fruits because they continue to ripen after harvest. Figure 1.2 Characteristics of fruits and vegetables affecting storage 1.2.2 Common storage problems in fruits and vegetables Several problems reduce the storage life of fruits and vegetables. Mechanical damage during harvesting or handling creates entry points for pathogens. Microbial spoilage caused by fungi and bacteria leads to rotting. Physiological disorders such as chilling injury occur when tropical produce is stored at very low temperatures. In addition, wilting due to water loss is common in leafy vegetables. These problems highlight the need for careful handling and appropriate storage conditions. Fill in the blank: Tropical fruits may suffer __________ injury when stored at very low temperatures.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.2 Common storage problems in fruits and vegetables 1.2.3 Strategies to extend storage life To extend the storage life of fruits and vegetables, several strategies are employed. Temperature management is crucial, with refrigeration slowing down respiration and microbial growth. Humidity control helps prevent wilting and shrivelling. Modified atmosphere packaging (MAP) reduces oxygen levels and increases carbon dioxide to slow ripening. Careful handling minimises mechanical damage, while sanitation practices reduce microbial contamination. These strategies, when combined, significantly prolong shelf life and maintain quality. Fill in the blank: Reducing oxygen and increasing carbon dioxide in packaging is known as __________ atmosphere packaging. Strategy Description / Notes Refrigeration Lowers respiration rate and slows microbial growth, extending shelf life of perishable produce.
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