Deterioration in fruits and vegetables

[Virtual Presenter] Deterioration in fruits and vegetables is welcome to today's lecture topic. Various factors responsible for spoilage of essential food items after harvesting we're going to explore..

[Audio] Deterioration in fruits and vegetables is mainly caused by the activities of bacteria and fungi, which invade the succulent nature of the produce. Common pathogens causing rots in fruits and vegetables include fungi such as Alternaria, Botrytis, Diplodia, Phomopsis, Rhizopus, Penicillium, and Fusarium, and among bacteria, Erwinia and Pseudomonas. These microorganisms directly consume small amounts of the food but damage the produce to the point that it becomes unacceptable due to rotting or other defects. Loss in quantity occurs when deep penetration of decay makes the infected produce unusable, while loss in quality occurs when the disease affects only the surface of the produce, causing skin blemishes that can lower the value of a commercial crop..

[Audio] Fruits and vegetables are cornerstones of a balanced diet, providing essential nutrients like vitamins, minerals, fiber, and antioxidants. They play a significant role in preventing chronic diseases such as heart diseases, diabetes, and cancer. The World Health Organization recommends a minimum of 400 grams of fruits and vegetables per day for preventing chronic diseases. Despite their importance in human health, a significant portion of fruits and vegetables deteriorate before reaching consumers, leading to waste and economic losses. According to estimates by the Food and Agriculture Organization, roughly one-third of all produced food is wasted globally, and fruits and vegetables have the highest wastage rates of any food type. This deterioration is mainly caused by the activities of bacteria and fungi, which invade the succulent nature of fruits and vegetables, causing pathological breakdown..

[Audio] Despite their importance in human health, a significant portion of fruits and vegetables deteriorate before reaching consumers, leading to waste and economic losses. According to estimates by the Food and Agriculture Organization, roughly one-third of all produced food is wasted globally, and fruits and vegetables have the highest wastage rates of any food type..

[Audio] The concept of post-harvest deterioration is not new and can be traced back to the early 19th century. The dawn of agricultural sciences recognized that harvested produce, specifically fruits and vegetables, were susceptible to spoilage. In the early 20th century, as industrialization rapidly advanced, new methods to prolong the shelf life of produce were developed, including cold storage, controlled atmosphere storage, vacuum storage, and the use of preservatives. Modern advancements include the use of sensor technology, nano-technology in packaging, and coatings made from nanoparticles, as well as the incorporation of (A-I ) and machine learning algorithms..

[Audio] Today's lesson will focus on the various factors that contribute to the deterioration of fruits and vegetables, including enzymatic reactions, insect infestation, pathogen infection, respiration rate, ethylene sensitivity, and physical damage. Enzymatic reactions, which refer to the natural enzymes present in produce, can cause spoilage and loss of quality. Insects can also damage fruits and vegetables, making them more susceptible to decay. Similarly, pathogens can lead to rot and unsafe consumption. Respiration rate and ethylene sensitivity can also impact shelf life, with high respiration rates and exposure to ethylene gas leading to faster spoilage. Finally, physical damage such as bruising can create entry points for microbial growth, increasing spoilage risk. Understanding and properly handling these factors is crucial for managing the quality and safety of fruits and vegetables..

[Audio] Slide number 7 of our presentation focuses on the topic "Deterioration in Fruits and Vegetables". As discussed in previous slides, deterioration is unavoidable in harvested fruits and vegetables. This slide will specifically discuss the biological process that causes deterioration in these perishable products. The most common and important biological process in harvested fruits and vegetables is oxidative breakdown. This process involves breaking down complex materials like carbohydrates and acids into simpler compounds such as carbon dioxide and water. This breakdown also produces energy, which is crucial for the survival of these products. It is worth noting that even after harvest, fruits and vegetables are still living and their cells continue to respire. This respiration process provides the necessary energy for the products to sustain themselves. Therefore, consuming fruits and vegetables that have been stored for too long is not recommended as their energy reserves may have depleted. The breakdown of stored food and water in the presence of oxygen results in the production of soluble foods, carbon dioxide, water, and heat. While this breakdown is a natural part of the deterioration process, it also leads to the loss of nutrients and quality in the fruits and vegetables. In conclusion, slide number 7 highlights the important role of oxidative breakdown in the deterioration of harvested fruits and vegetables. In the following slides, we will further explore the various factors that contribute to this process and how we can slow down the deterioration of these perishable products..

[Audio] Slide number 8 is where we will be discussing the deterioration of fruits and vegetables. One of the main reasons for this is the large amount of organic acids in the vacuoles. These acids are used in the mitochondria for the T-C-A cycle. It is interesting to note that when these acids are completely oxidized, more carbon dioxide is produced than oxygen consumed. To measure this, the respiratory quotient (R-Q---) has been developed. RQ is a simple formula that tells us the ratio of carbon dioxide produced to oxygen consumed. The RQ value can vary depending on the type of substrate being oxidized. For instance, when acids are fully oxidized, the RQ value is greater than 1, indicating an excess amount of carbon dioxide being produced. For glucose, the RQ value is exactly 1, showing a balance between carbon dioxide production and oxygen consumption. For fatty acids, the RQ value is less than 1, meaning less carbon dioxide is produced compared to oxygen consumed. Understanding RQ is crucial in determining the freshness and quality of fruits and vegetables. It helps us identify the substrate being utilized and how efficiently it is being oxidized. This information can aid in improving storage and preservation methods to decrease the deterioration of these perishable foods..

[Audio] This training video focuses on the topic of "Deterioration in fruits and vegetables" and discusses the classification of these items based on their respiration rates. On slide number 9, a table is displayed showing the different classes and their corresponding respiration rate ranges at a temperature of 5 degrees Celsius. It is important for higher education teachers to understand this information in order to properly store and preserve fruits and vegetables. The table shows five classes based on respiration rates: very low, low, moderate, high, and extremely high. Starting with the very low class, which has a respiration rate of less than 5 milligrams of C-O-2 per kg per hour, items such as nuts, dates, dry fruits, and vegetables are included. These have a slow respiration rate and are less likely to deteriorate. Moving on to the low class, with a range of 5-10 milligrams of C-O-2 per kg per hour, this includes apples, citrus fruits, grapes, garlic, onions, and potatoes. These items have a slightly higher respiration rate compared to the very low class. The moderate class has a range of 10-20 milligrams of C-O-2 per kg per hour and includes fruits like apricots, bananas, cherries, peaches, and pears, as well as vegetables like cabbage, carrots, lettuce, and peppers. These items have a moderate respiration rate, making them more susceptible to deterioration. The high class has a respiration rate of 20-40 milligrams of C-O-2 per kg per hour and includes fruits like strawberries and raspberries, as well as vegetables like cauliflower and avocados. These items have a higher respiration rate and need to be handled and stored properly to prevent deterioration. Lastly, the extremely high class has a respiration rate of over 60 milligrams of C-O-2 per kg per hour and includes vegetables like asparagus, broccoli, mushrooms, peas, and spinach. These items have a very high respiration rate and are highly prone to deterioration. Understanding the respiration rates of fruits and vegetables is crucial in extending their shelf life and maintaining their quality. This knowledge can also help in selecting the best storage methods for different types of produce..

[Audio] We will now discuss the different factors that contribute to the deterioration of fruits and vegetables, starting with slide number 10. It is important to understand these factors in order to preserve and extend the shelf life of these perishable foods effectively. These factors can be divided into two main categories plant factors and environmental factors. Let's begin with plant factors. One factor to consider is the level of soluble sugars present in the fruit or vegetable. The amount of sugars directly affects the rate of respiration, meaning that more sugars will lead to a faster deterioration. Glucose is the primary sugar in fruits and vegetables and greatly impacts the rate of respiration. Another plant factor to consider is the proportion of living cells in the fruit or vegetable. This also affects the rate of respiration, as living cells require a constant supply of energy. Respiration is essential for the fruit or vegetable's lifespan. In summary, both the levels of soluble sugars and proportion of living cells play significant roles in the deterioration of fruits and vegetables. Understanding these factors will aid in properly preserving and storing these perishable foods. Let's move on to the next slide where we will discuss the environmental factors contributing to the deterioration of fruits and vegetables..

[Audio] In slide number 11, we will discuss the third factor that affects the deterioration of fruits and vegetables: water content. This factor is directly related to the respiration process in produce. Simply put, products with higher water content will respire and deteriorate at a faster rate. This is why succulent products, such as lettuce, will respire more quickly than non-succulent ones like potatoes, sweet potatoes, or peppers. It's important to consider that the respiration rate can also be influenced by storage conditions and ripeness. However, the water content remains a crucial factor in understanding the deterioration of fruits and vegetables. Therefore, it's important to take note of the water content and its impact on respiration rate when assessing the quality of produce. This will help guide decisions on how to handle and store fruits and vegetables to maintain their freshness and quality. Now, let's move on to the next factor that contributes to produce deterioration. Thank you for your time and see you on the next slide..

[Audio] We are currently on slide number 12 out of 25 in our presentation on "Deterioration in Fruits and Vegetables". This slide will cover the factors that influence the rate of respiration in fruits and vegetables. One important factor is the concentration of oxygen and carbon dioxide. Respiration is a process that requires oxygen and produces carbon dioxide, so it follows that a higher oxygen concentration will result in a higher rate of respiration, while a lower oxygen level will decrease the rate. Temperature is also a significant factor in respiration. Generally, higher temperatures lead to an increase in respiration rate due to the increased metabolic activity of the fruits and vegetables. It is important to monitor and regulate these factors in order to prevent or slow down the deterioration of fruits and vegetables. For example, storing them in an environment with lower oxygen levels and temperatures can extend their shelf life. Understanding the impact of oxygen concentration and temperature on respiration, we will now move on to the next slide to discuss the role of ethylene in fruit and vegetable deterioration..

[Audio] Next, we will discuss the second cause of deterioration in fruits and vegetables: transpiration. This natural process is responsible for the deterioration of produce, resulting in both quantitative losses, such as weight decrease, and qualitative losses, such as a loss in appearance with wilting and shriveling. Transpiration can also cause a change in texture, making the produce become soft instead of crisp. It is important to note that transpiration can also affect the nutritional quality of fruits and vegetables. Understanding this process is crucial in effectively combating deterioration and ensuring that produce remains fresh and high-quality. Let's move on to the next slide to learn about the other causes of deterioration..

[Audio] Factors that can contribute to the deterioration of fruits and vegetables include plant factors. Plants are composed of different tissues, which can vary in their level of differentiation. This refers to the specialization and development of cells within a tissue. This can affect the transpiration process, which is the loss of water from the plant's surface. Generally, tissues with less differentiation and more succulence will have a higher water content and lose water more quickly than highly differentiated and less succulent tissues. For example, plants like asparagus and spinach will lose water faster than mature cabbage, onions, and celery. Understanding these plant factors and their impact on transpiration can help us better manage the post-harvest life of fruits and vegetables. Now, let's discuss other factors that can also contribute to deterioration in fruits and vegetables..

[Audio] Slide number 15 will cover the topic of the outer cover of fruits and vegetables, which is composed of two types of tissues epidermis and periderm. The epidermis, made up of a single layer of living cells, serves as a protective barrier for the fruit or vegetable. Additionally, the layer of wax present in the epidermis helps to slow down transpiration, preventing the loss of water through the skin. Plant products with a cutinized epidermis, meaning an epidermis with a layer of wax, have been found to decrease in size at a slower rate during storage compared to those with a non-cutinized epidermis. This is due to the protective layer of wax that helps to retain moisture and prevent dehydration. Understanding the importance of the outer cover of fruits and vegetables is crucial in maintaining their quality during storage. It is especially important to preserve the layer of cutinized epidermis to prevent rapid deterioration. Slide number 16 will further explore the different types of periderm tissues and their role in the deterioration of fruits and vegetables. So, stay tuned and take notes as we continue our discussion on deterioration in fruits and vegetables..

[Audio] Periderm, the outer layer of the skin, plays a vital role in the storage and preservation of fruits and vegetables. A well-developed and non-injured periderm allows these products to retain moisture and stay fresh for a longer period of time, whereas a poorly developed or damaged periderm leads to quicker deterioration. This is particularly important during storage, as fruits and vegetables are highly perishable and can quickly deteriorate if not stored correctly. The periderm acts as a protective barrier against external factors such as bruising and injuries, and its integrity is crucial for maintaining the quality and shelf life of these products..

[Audio] Environmental factors play a crucial role in the deterioration of fruits and vegetables. Temperature and relative humidity are two key factors that significantly impact the quality and lifespan of produce. At high temperatures, there is a greater rate of transpiration and shrinkage compared to low temperatures, which can lead to dehydration and a shorter shelf life. Conversely, high relative humidity slows down the rate of transpiration, reducing the risk of dehydration. However, low relative humidity can accelerate transpiration, resulting in rapid dehydration and spoilage. Proper storage conditions, including optimal temperature and relative humidity levels, are essential to maintain the quality and longevity of fruits and vegetables..

[Audio] Ethylene, a colorless gas with a sweetish odor and taste, was first discovered in 1796. It has several properties, including being an asphyxiant and anesthetic, and is highly flammable. Ethylene has physiological effects on crops, and was first identified as a volatile chemical produced by ripening apples by Gane in 1934. Climacteric fruits, such as apples, bananas, and tomatoes, produce a significant amount of ethylene during development, whereas non-climacteric fruits, like citrus fruits and strawberries, do not. The threshold level of ethylene needed to induce ripening is only 0.001 micro litre, making even a small amount of ethylene significant in the ripening process..

[Audio] Classification of fruits and vegetables according to their ethylene production rate is presented on slide 19. The classification ranges from very low to very high, with corresponding examples of fruits and vegetables. The very low class range has a value of less than 0.1 mL of ethylene gas per kg of produce, per hour, and includes commodities such as asparagus, cherry, strawberry, cauliflower, potato, and leafy vegetables. The low class range of 0.1-1.0 mL of ethylene gas per kg of produce, per hour, includes items like blueberry, cranberry, cucumber, okra, persimmon, pineapple, pumpkin, and watermelon. The moderate class range of 1.0-10.0 mL of ethylene gas per kg of produce, per hour, includes fruits like banana, fig, guava, melon, mango, and tomato. The high class range of 10.0-100.0 mL of ethylene gas per kg of produce, per hour, includes fruits such as apple, apricot, avocado, kiwi fruit, papaya, pear, peach, and plum. Finally, the very high class range of over 100.0 mL of ethylene gas per kg of produce, per hour, includes fruits like passion fruit, sapota, and cherimoya..

[Audio] Ethylene plays a significant role in the ripening process of fruits and vegetables, binding to specific receptors and triggering the maturation process. Not all fruits and vegetables respond to ethylene in the same way, with some experiencing an initial respiratory increase before ripening, while others do not. Understanding ethylene's role is crucial for proper storage and preservation, allowing us to control ethylene levels and prolong shelf life..

[Audio] Ethylene plays a crucial role in the ripening process of fruits. Its sensitivity varies depending on the type of plant tissue and the levels of oxygen and carbon dioxide present. Not only does ethylene influence the ripening, flavor, and color formation of fruits, but it also affects disease tolerance, chilling injury, sprouting, growth, texture, respiration, nutrient content, abscission, senescence, and toxin formation in plants. Furthermore, ethylene causes the de-greening of bananas and oranges, and it bleaches the green color of leafy vegetables like celery, cabbage, and broccoli. As an initiator or contributor to the ripening process, ethylene's impact on fruits cannot be overstated..

[Audio] Ethylene is a natural plant hormone that plays a significant role in the ripening process of fruits and vegetables. To control ethylene production, we have several options available. One method is to absorb it using materials such as activated charcoal, activated carbon, hydrated aluminum silicate, or zeolite. This can be done by placing these materials in the storage room where the produce is kept. Another approach is.

[Audio] Mechanical damage is a significant factor contributing to the deterioration of fruits and vegetables. There are three main types of mechanical damage: roller bruising, impact bruising, and compression bruising. Roller bruising occurs when fruits or vegetables rub or vibrate against another surface, resulting in damage to the surface. Impact bruising occurs when products are dropped onto a hard surface, with the damage potentially not being visible on the surface initially, but symptoms of internal damage appearing later. Compression bruising occurs when fresh produce is squeezed into a space that is too small, causing pressure that leads to cell breakdown and deterioration. Mechanical damage not only affects the physical appearance of the product but also its nutritional value and spoilage rate. Proper handling and packaging procedures are essential in preventing mechanical damage and ensuring the quality of fruits and vegetables..

[Audio] Physiological breakdowns in fruits and vegetables occur when they are exposed to undesirable temperatures. Freezing injury occurs when produce is stored at or below its freezing temperature, resulting in defects such as discoloration, softening, and loss of texture. Chilling injury occurs when produce is stored at a temperature below its desired storage temperature, causing symptoms like discoloration, water-soaked spots, and accelerated ripening. Heat injury results from exposure to direct sunlight or excessively high temperatures, leading to defects like sunburn, bleaching, scalding, uneven ripening, and excessive softening. Low oxygen levels during storage can also cause physiological problems, including the loss of texture, structure, and microbial damage. Proper storage and transportation methods are necessary to prevent these physiological breakdowns from occurring..

[Audio] As we come to the final slide of our presentation, we will be discussing the most common symptom of deterioration in fruits and vegetables, which is mainly caused by the activities of bacteria and fungi, specifically yeast and mould. The succulent nature of fruits and vegetables makes them highly susceptible to invasion by these microorganisms. Common pathogens responsible for causing rots in fruits and vegetables include fungi such as Alternaria, Botrytis, Diplodia, Phomopsis, Rhizopus, Penicillium and Fusarium, as well as bacteria like Erwinia and Pseudomonas. These microorganisms do not only consume small amounts of the food, but they also cause extensive damage to the produce to the point where it becomes unacceptable due to rotting or other defects, resulting in both quantity and quality loss. Quantity loss occurs when the decay penetrates deep into the produce, rendering it unusable, while quality loss happens when the disease only affects the surface of the produce, causing skin blemishes that can significantly lower the value of a commercial crop..