Crop Science 3: Post-harvest handling technology

Crop Science 3: Post-harvest handling technology

1. 7. Packaging is the technology to ensure adequate protection and safe delivery of produce from the farm to the ultimate consumer. is the act of putting commodities into the package and preparing for shipment or transport, while, package is the structure designed to contain the produce.

2. Packaging Materials All packaging materials should be made of food contact grade materials to assure that toxic compounds in the packaging materials do not leach out of the package and into the produce. Toxic chemical! residues may be present in some packaging materials due to use of recycled base materials

3. Packaging Materials Fresh fruits and vegetables are generally packed in bamboo baskets, plastic crates, plastic bags, or nylon sacks for transportation, in many developing countries. Containers with sharp edges, liners or cushion must be provided to avoid crop damage. Pack produce only to full capacity. Ovoid over packing under packing. Use rigid containers such as wooder or plastic crates is always recommended but the economic aspect must be considered.

4. Function of a package: Facilitate easy handling Protects produce Sell the product must be appealing to the consumers. Inform the consumer

5. Causes of damage during handling a. Mechanical- there is alteration in the appearance of a commodity due to physical factors such as dropping, throwing, pressing, bouncing or rubbing against a rough surface b. Pathological - this is damage due to microbiological agents. c. Physiological -this leads to abnormal flavor, texture, and color due to unfavorable environmental factors.

6. Kinds of mechanical damage Bruising Wounding Distortion Abrasion

7. Source of damage a. Impact - this is damage made by collision between the produce and a hard surface. It is related to the amount of damage absorbed by the produce. b. Compression - occurs when a heavy weight is placed on top of the commodity. Other terms for compression are pressure, top loading or dead load. No physical movement is necessary for damage to occur.

8. Source of damage It occurs in: over packing occurs, packing in flexible container. stacking is too high or improper. very deep container for a particular commodity c. Vibration - damage occurs when the produce is repeatedly shaken for prolonged period

9. Kinds of Packages According to a) material and b) design Burlap Fibrous material Plastics Paper sheets

10. Kinds of Packages According to material Wood

11. Modern packaging must comply with the following requirements, wills et al. (1989): a.) The package must have sufficient mechanical strength to protect the contents during handling, transport, and stacking. b.) The packaging material must be free of chemical substances that could transfer to the produce and become toxic to man. c.) The package must meet handling and marketing requirements in terms of weight, size, and shape. d.) The package should allow rapid cooling of the contents. Furthermore, the permeability of plastic films to respiratory gases could also be important.

12. Modern packaging must comply with the following requirements, wills et al. (1989): e.) Mechanical strength of the package should be largely unaffected by moisture content (when wet) or high humidity conditions. f.) The security of the package or ease of opening and closing might be important in some marketing situations. g.) The package must either exclude light or be transparent. h.) The package should be appropriate for retail presentations.

13. Modern packaging must comply with the following requirements, wills et al. (1989): i.) The package should be designed for ease of disposal, re-use, or recycling. j.) Cost of the package in relation to value and the extent of contents protection required should be as low as possible.

14. Modified Atmosphere Packaging (MAP) Consist of altering the composition of air surrounding produce to extend postharvest life. It is used: 1) to supplement refrigeration 2) may be used even under non-refrigerated conditions for shorter period of time.

15. Modified Atmosphere (MA) vs Controlled Atmosphere (CA) Differ only in the degree of control with CA involving tighter control of gas composition MA usually simpler and cheaper MA best suited to smaller volumes (i.e.<20kg)

16. Air Modification Passive modification - Use of a barrier to air exchange b/w the immediate environment of the commodity and the outside air. - In MAP - the produce is wrapped individually or in unit containers (e.g. cartons or retail packs) - Shrouding. Enclosure of a stack of cartons in plastic film

17. Air Modification In the above systems: - Commodities continuously take in oxygen (O,) and give off carbon dioxide (CO2), leading to decline in O, levels and accumulation of (CO2) - Use of semi-permeable membrane allows the exit of CO2 and entry of nitrogen (N2) hut prevents entry of O2

18. Air Modification 2. Active modification - Introduction of a gas mix of predetermined composition with or without partial or complete removal of air within the pack. e.g. commodities in cartons are shrouded w/ plastic film, then air is sucked out and replaced with a gas mix enriched with CO2.

19. Other Gases used in MA: Sulfur dioxide- a fungistat for use in grapes Carbon monoxide- inhibits discoloration and disease in cut lettuce and citrus Outcome when commodity subjected to MA MA → metabolism slows down → longer storage life In some cases: MA → increased relative humidity (RH) → reduced weight loss (enclosure of produce in perforated polyethylene bag)

20. Uses of MAP Storage Transport/Shipment Retail display

21. Beneficial Effects of MAP 1. Delays senescence - delays ripening of fruits - delays yellowing of leaves - delays softening 2. Reduces moisture loss/ wilting 3. Reduces produce sensitive to ethylene

22. Beneficial Effects of MAP 4. Prevents development of some physiological disorders e.g. chilling injury 5. Inhibits development of certain diseases e.g. Botrytis rot in strawberry 6. Helps inhibit browning e.g. peeled young coconut, minimally processed produce

23. Harmful Effects 0f MAP (If MAP is not properly managed) Enhanced disease development due to elevated RH Abnormal ripening as a result of excessively low O2 and/ or high CO2 leading to off-odors and off-flavors Aggravation of some physiological disorders e.g. blackheart in potato

24. Precautions Pack only clean and damage free commodities. Injured commodities release ethylene which can hasten deterioration. Spread of disease is highly probable in MA? due to high humidity inside the pack Cull out ripening fruits which release ethylene Keep MA- packed commodities in a relatively cool place if not refrigerated to avoid disease and /or physiological disorders Provide diffusion holes (i.e. perforations or pinpricks) to prevent extreme changes in gas composition (e.g. very low O2 or high CO2, high RH)

25. Recent successes in the use of map for reducing postharvest losses in fresh fruits and vegetables are as follows: Broccoli Normal Storage 3-5 days after harvesting the flowers change from green to yellow. MAP and storage at 4-7 °C Shelf life of 14 days, the fresh green flowers and crispness are retained.

26. Recent successes in the use of map for reducing postharvest losses in fresh fruits and vegetables are as follows: Parsley Normal Storage -Shelf life: 3-5 days MAP and storage at 1-2°C-Shelf life of up to 25 days, and retains fresh green color

27. Recent successes in the use of map for reducing postharvest losses in fresh fruits and vegetables are as follows: Banana Normal Storage-Shelf life of 5-7 days MAP and storage at 13-14 °C- Shelf life of up to 45 days

28. Recent successes in the use of map for reducing postharvest losses in fresh fruits and vegetables are as follows: Green bean Normal Storage-Shelf life of 3-7 days MAP and storage at 5-7 °C- Shelf life up to 16 days

29. 8. Transportation Fresh produce is primarily transported by road, from farmer to consumer. A marketing concern is that fresh produce should be of the highest quality and should be kept in the best condition during transportation.

30. 8. Transportation Minimizing losses during transportation, necessitates that special attention be given to vehicles, equipment, infrastructure and handling.

31. Vehicles used in transporting fresh produce Non-refrigerated vehicles are generally open-sided trucks, with wire mesh frames. This type of transportation is inexpensive, convenient and easy. Truck can be used for the delivery of fresh produce, other goods and passengers when required. Layers of produce are not, however, separated in order prevent heat generation. Often the produce is stacked too high.

32. Vehicles used in transporting fresh produce

33. Major causes of losses during the non-refrigerated transportation of fresh produce, are: • Improper handling during loading and unloading • Over loading without separation of produce which leads to overheating and mechanical injury to produce at the bottom of the stack • Rough roads • Lack of ventilation of the produce

34. Vehicles used in transporting fresh produce 2. Refrigerated Vehicles Produce is best shipped in temperature controlled refrigerated trucks Pre-cool the vehicles prior to loading Maintaining perishables below 5°C even while being transported to destination markets will extend shelf-life and significantly reduce the growth rate of microbes including human pathogens.

35. Vehicles used in transporting fresh produce Temperatures used for transporting chilling sensitive produce will not protect against the growth of most pathogens Trucks used during transportation should be cleaned and sanitized on a regular basis. Trucks which have been used to transport live animals, animal products or toxic materials should never be used to transport crops.

36. Types of Storage for Perishables Crops: Refrigerated storage This is the most effective method of prolonging the storage life of fruits and vegetables. The fruits and vegetables have their own optimum temperature and relative humidity at which they keep fresh for longer period, Table 2 and 3.

37. Types of Storage for Perishables Crops: The cold room should have the desired temperature and relative humidity. The commodities should be cooled as soon as possible, Root and bulb crops should be cured before storing for better protection against microorganisms. Temperature is the single most important tool for maintaining postharvest quality.

38. The five most common cooling methods; 1.1) Room cooling an insulated room or mobile container equipped with refrigeration units. Room cooling is slower than other methods. Depending on the commodity, packing unit, and stacking arrangement, the product may cool too slowly to prevent water loss, premature ripening, or decay.

39. The five most common cooling methods; 1.2) Forced-air cooling fans used in conjunction with a cooling room to pull cool air through packages of produce. Although the cooling rate depends on the air temperature and the rate of airflow, this method is usually 75 to 90% faster than simple room cooling.

40. The five most common cooling methods; 1.3.Hydrocooling showering produce with chilled water to remove heat, and possibly to clean produce at the same time, The use of a disinfectant in the water is essential. Hydrocooling is not appropriate for all produce.

41. The five most common cooling methods; Waterproof containers or water-resistant waxed corrugated cartons are required. Currently waxed corrugated cartons have limited recycling or secondary use outlets, and reusable, collapsible plastic containers are gaining popularity.

42. Table 2. Recommended Storage Temperature(T) and Relative Humidity(RH) of Selected Tropical and Subtropical Fruits Commodity T(ºC) RH(%) Storage life Avocado 7 85-90 2-3 wk Banana (green) 13-14 90-95 1-4 wk Breadfruit (rimas) 13-15 85-90 2-6 wk Calamondin (calamansi) 9-10 90 2 wk Canistel (tiesa) 13-15 85-90 3 wk Carambola (balimbing) 5-10 85-90 4-7 wk Durian 10-13 85-90 2-3 wk Grapes -0.5-0 85-90 3-8 wk Guava 10-13 90 2 wk Jackfruit 13 85-90 2-6 wk Commodity T(ºC) RH(%) Storage life Lanzones 11-14 85-90 2 wk Lemon 7-10 85-90 2-3 wk Lime 9-10 85-90 6-8 wk Longan 1.5 90-95 3-5 wk Lychee 0-2 90-95 3-5 wk Mango 13 85-90 2-3 wk Mangos teen 13 85-90 2-3 wk Oranges, mandarin 3-4 85-90 3-5 wk Papaya 10-13 85-90 2-3 wk Pineapple 7-10 85-90 2-3 wk

43. Table 2. Recommended Storage Temperature(T) and Relative Humidity(RH) of Selected Tropical and Subtropical Fruits Commodity T(ºC) RH(%) Storage life Pumelo (suha) 7-9 85-90 4-6 wk Rambutan 12 90-95 1-2 wk Santol 7-9 85-90 3 wk Sapota (chico) 15-20 85-90 1-2 wk Soursop (guyabano) 13 85-90 1-2 wk Starapple 3 90 3 wk Strawberry -0.5-0 90-95 5-10 d Sugar apple (atis) 7 90-95 3-8 wk Tamarind 7 90-95 3-4 wk Source: Bautista, O.K and E.B. Esguerra. 2007. Postharvest Technology for Southeast Asian Perishable Crops, UPLB, Laguna, Philippines

44. Table 3. Recommended Storage Temperature(T) and Relative Humidity(RH) of Selected Tropical and Subtropical Vegetables Commodity T(ºC) RH(%) Storage life Amaranth 0-2 95-100 10-14 d Asparagus 0-2 95-98 2-3 wk Bean, snap 4-7 95-98 7-10 d Bean, lima (in pod) 5-6 95 5 d Bittermelon 12-13 85-90 2 wk Brocolli 95-98 10-14 d Cabbage 98-100 3-6 wk Carrot 95-100 4 wk Cauliflower 95-98 2-4 wk Celery 95-98 2-4 wk Commodity T(ºC) RH(%) Storage life Chayote 7 85-90 1-2 wk Chinese Cabbage 95-100 2-3 mo Corn, sweet 95-98 4-8 d Cucumber 10-13 90-95 10-14 d Eggplant 12-15 90-95 7 d Garlic 90-70 6-7 mo Ginger 13 65-75 6-4 mo Leek 95-100 3 mo Lettuce 0-1 95-100 2-3 wk Melon, honeydew 7-10 90-95 2-3 wk

45. Table 3. Recommended Storage Temperature(T) and Relative Humidity(RH) of Selected Tropical and Subtropical Fruits Commodity T(ºC) RH(%) Storage life Okra 7-10 90-95 2-3 wk Onion, bulb 65-70 6-8 mo Parsley 95 2-3 wk Peas 0-1 95 1-2 wk Pepper, sweet 7-10 90-95 2 wk Potato 4 95 3-5 mo Source: Bautista, O.K and E.B. Esguerra. 2007. Postharvest Technology for Southeast Asian Perishable Crops, UPLB, Laguna, Philippines Commodity T(ºC) RH(%) Storage life Radish 95 3-4 wk Squash 5-10 95 1-2 wk Taro 7-10 85-90 3-5 mo Tomato 10-13 85-90 7-10 d Watermelon 10-15 90 2-3 wk Winged bean 10 90 2-3 wk

46. The five most common cooling methods; 1.4) Top or liquid icing an effective method to cool tolerant commodities, and equally adaptable to small- or large-scale operations.

47. The five most common cooling methods; It is essential that you ensure that the ice is free of chemical, physical, and biological hazards Keep vegetables just above their freezing point (0°C), or just above their chilling point for chilling sensitive plants as asparagus, broccoli, and Brussels sprouts; 5-8 °C for moderately chilling sensitive vegetables, beans, peas, cucumbers, peppers, summer squash, pumpkins, some melons, and potatoes; 13-15 °C for highly chilling sensitive eggplant and tomato.

48. The five most common cooling methods; 1.5) Vacuum cooling - uses a vacuum chamber to cause the water within the plant to evaporate, removing heat from the tissues.

49. The five most common cooling methods; This system works well for leafy crops that have a high surface-to-volume ratio, such as lettuce, spinach, and celery, The operator may spray water onto the produce before placing it into the vacuum chamber. As with hydro-cooling. proper water disinfection is essential. The high cost of the vacuum chamber system restricts its use to larger operations.

50. 2. Common Methods (Unrefrigerated) 2.1) In ground storage for potatoes and sweet potatoes This means intentionally leaving the crop on the ground after the crop has attained the size (for sweet potato and taro) and characteristics of a mature vegetable (for potato). Harvest can be delayed for several months for sweet potato and three to six months for potato.

51. 2. Common Methods (Unrefrigerated) 2.2) Evaporative cooling in hot and dry areas Evaporative cooling utilizes the evaporation of water using heat of respiration of the vegetables. Water should be near around the vegetables. Hot, dry air is thus cooled when it flows through a wet surface. The temperature may drop by 1°C- 5°C and relative humidity increase by 20-30%, depending on the prevailing temperature and relative humidity.

52. Some applications of evaporative cooling are: a. Sprinkling vegetables with water. b. Keeping vegetables in moist earthen jars. c. Keeping vegetables inside drip coolers. Materials that can absorb water and evaporated. d. Clamp storage for low temperature areas. Vegetables are placed in piles or pits or trenches.

53. 2. Common Methods (Unrefrigerated) 2.3) Ventilated storage Provision with adequate ventilation. Hanging onions and garlic.

54. 2. Common Methods (Unrefrigerated) 2.4) Diffused light storage for potatoes To avoid greening of potatoes which become poisonous due to solanin (for consumption). If for planting purposes produce vigorous and green sprouts.

55. Ten Important Guidelines for Postharvest Handling in General: 1. Maturity 9. Coordination 2. Reduce injuries 10. Training 3. Protect product 4. Cleanliness & sanitation 5. Pack carefully 6. Palletize 7. Cool 8. Know product

56. RIPENING Is a series of biochemical and physical processes that cause an immature fruit to develop all the desirable aesthetic and edibility characteristics of its species.

57. When ethylene is externally applied, the threshold level of ethylene is attained much faster so the autocatalytic production of ethylene occurs much faster. as a result; A fruit need not be exposed to externally applied ethylene for a long but only up to the time that the autocatalytic production of ethylene starts; An ethylene-producing chemical has no other effect except to trigger production of more ethylene; Eating ethylene-treated fruits is not harmful to people.

58. Fruits that need to be picked ripe have the following characteristics: No capable of ripening off the plant since there is no further development of even when harvested" at the ripe stage, full color flavor after harvest. Development may not be achieved if the growing temperature is not favorable for the enzyme responsible for the development of the particular color.

59. Fruits that need to be picked ripe have the following characteristics: Have no starch that can be converted into sugar- there may be however, a slight improvement in the taste if they kept for some time after harvest due to faster breakdown of acids than sugars as in citrus. Moisture in the fruit resulting in higher concentration of sugars relative to water as in lanzones where the loss in moisture is due to drying of the latex and transpiration.

60. Fruits that need to be picked ripe have the following characteristics: There is hardly change in respiration after harvest, hence, are non-climacteric, treatment of ethylene will only improve the color as in oranges in which case the process is called degreening.

61. Degreening involves treatment with ethylene to improve the color of non- climacteric fruits like citrus and climacteric fruits that that do not attain the desired color like Cavendish bananas.

62. Introduce ethylene or acetylene in the environment of the fruit. Ethylene can be applied as a gas or as an ethylene-releasing compound like 2- chloroethyl phosphonic acid (CEPA) also known as ethephon . Acetylene could be applied as a gas or generated from calcium carbide. Both acetylene and ethylene could be derived from smoke of slowly burned organic materials. Expose to bio-ethylene, which is ethylene from leaves or fruits.

63. Treatment with acetylene applied as a gas also and generated from calcium carbide (CaC2). As a gas, the activity of acetylene is 100 times less than of ethylene, so it is less effective. It is explosive at 2.5-8% volume of acetylene per volume of air.

64. Treatment with acetylene Cac2 is cheap and readily available. It is usually sold as solid irregular-sized chunks stored in airtight containers because of its highly hygroscopic nature. It is used as a ripening agent.

65. Reaction When CaC2 reacts with water (from transpiring fruits), acetylene gas, which mimics the ripening effects of ethylene gas, is released. CaC2 + H2O HC=CH + CaO Calcium carbide Water Acetylene Calcium oxide

66. Bioethylene This the ethylene release from biological source, mainly leaves and ripening fruits.

67. Sources of bioethylene Leaves of certain plant species Ipil-ipil Rain tree or acasia

68. Sources of bioethylene 2. Fruit - Climacteric fruit such as purple passion fruit is the highest ethylene producer so far recorded, about 464.6 nL/g/h and this high rate is sustained for about 12 days. Purple passion fruit is available only in the highland.

69. Sources of bioethylene Saba banana produces 13.05 nL/g/h ethylene and improved pope tomatoes, 3.16 nL/g/h for 7 days and 6 days respectively.

70. End of Lecture 