FOOD week 6-2 Postharvest management and quality of Food
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Questions and Answers

Which factor can affect the taste of different cultivars?

  • Genetics (correct)
  • Climate
  • Crop nutrition
  • Agronomy
  • What effect does cool temperature have on banana fruit filling?

  • Increased sweetness
  • Decreased acidity
  • Abnormal shapes
  • Slowed degreening (correct)
  • Which nutrient increases the acidity in citrus?

  • Salt
  • Nitrogen (correct)
  • Phosphorus
  • Potassium
  • What is the main cause of internal dryness in Imperial mandarins?

    <p>Granulation</p> Signup and view all the answers

    What happens to the juice sacs in mandarins affected by internal dryness?

    <p>They become granular and opaque white</p> Signup and view all the answers

    Which method is NOT used for postharvest temperature management?

    <p>Freezing</p> Signup and view all the answers

    What is the optimal temperature for chilling insensitive produce?

    <p>-3 to -0.5°C</p> Signup and view all the answers

    Which region is more likely to have chilling sensitive produce?

    <p>Tropical</p> Signup and view all the answers

    What is the arbitrary threshold temperature between chilling sensitive and insensitive produce?

    <p>12°C</p> Signup and view all the answers

    Which factor is NOT part of the transport cold chain for temperature management?

    <p>Refrigerated distribution &amp; retail</p> Signup and view all the answers

    Which organic acids are stored in the vacuole of fruits and vegetables?

    <p>Citric and malic acid</p> Signup and view all the answers

    What happens if the tonoplast (vacuolar membrane) is damaged during storage?

    <p>Leakage of acids damages the cell</p> Signup and view all the answers

    Which method can be used to suppress ethylene and slow down ripening?

    <p>All of the above</p> Signup and view all the answers

    Which fruits require a storage temperature of 7°C?

    <p>Avocado, pepper, pineapple, pomegranate, snap bean</p> Signup and view all the answers

    What is the purpose of administering ethylene to fruits like tomatoes and avocados?

    <p>To induce ripening</p> Signup and view all the answers

    Which gas is used as an ethylene inhibitor to delay ripening and fruit drop in some plants?

    <p>1-MCP</p> Signup and view all the answers

    At what concentration can ethylene have a detrimental effect on produce shelf-life and quality?

    <p>0.5 ppm</p> Signup and view all the answers

    Which ethylene scrubber is starting to be incorporated into active packaging?

    <p>KMnO4</p> Signup and view all the answers

    What is the registered trade name for Aminovinylglycine (AVG), an ethylene inhibitor applied preharvest to delay ripening and fruit drop in some plants?

    <p>ReTain</p> Signup and view all the answers

    When should ReTain be applied to delay apple maturity and allow further growth?

    <p>21-28 days prior to harvest</p> Signup and view all the answers

    Which pigmented phytochemical is responsible for the green color in plants?

    <p>Chlorophyll</p> Signup and view all the answers

    Which pigmented phytochemicals are responsible for the red/orange color in plants?

    <p>Carotenoids</p> Signup and view all the answers

    Which pigmented phytochemicals are responsible for the yellow color in plants?

    <p>Carotenoids</p> Signup and view all the answers

    Which pigmented phytochemicals are responsible for the red/mauve/blue/purple color in plants?

    <p>Anthocyanins</p> Signup and view all the answers

    What causes the yellowing of bananas during ripening?

    <p>Loss of chlorophyll</p> Signup and view all the answers

    What causes the yellowing of bananas during ripening?

    <p>Loss of chlorophyll</p> Signup and view all the answers

    Which pigmented phytochemicals are responsible for the red/orange color in plants?

    <p>Carotenoids</p> Signup and view all the answers

    What is the purpose of administering ethylene to fruits like tomatoes and avocados?

    <p>To delay ripening</p> Signup and view all the answers

    Which of the following is a cause of enzymatic browning in fruits and vegetables?

    <p>Physical damage due to mishandling</p> Signup and view all the answers

    Which factor is mainly associated with transportation damage in fruits and vegetables?

    <p>Vibration</p> Signup and view all the answers

    Which fruit is particularly challenging to handle postharvest due to its shape?

    <p>Banana</p> Signup and view all the answers

    Which of the following is most closely associated with the firmness and texture of fruits and vegetables?

    <p>Cell wall structure and composition</p> Signup and view all the answers

    Which components make up the primary cell walls in plants?

    <p>Cellulose microfibrils and pectins</p> Signup and view all the answers

    What is a common mechanism for modifying cell wall structure and strength during ripening?

    <p>Depolymerisation of matrix glycans</p> Signup and view all the answers

    What is the main cause of textural change in fruits and vegetables during storage?

    <p>Desiccation</p> Signup and view all the answers

    What are the consequences of water loss in produce during storage?

    <p>Shrivelling, softening, loss of appearance, loss of saleable weight, toughening</p> Signup and view all the answers

    Which factor affects the rate of water loss in produce during storage?

    <p>Surface area to volume ratio</p> Signup and view all the answers

    What are the two main factors that determine a fruit's characteristic flavor?

    <p>Sugar/acid balance and production of aroma volatile compounds</p> Signup and view all the answers

    What is the purpose of GC-MS in analyzing ripe fruit?

    <p>To identify volatile compounds contributing to flavor and aroma</p> Signup and view all the answers

    What is the role of diacetyl in fruit flavor?

    <p>Imparts a buttery flavor</p> Signup and view all the answers

    What is the role of furaneol in fruit flavor?

    <p>Imparts a strawberry flavor</p> Signup and view all the answers

    How many volatile compounds may a ripe fruit contain that contribute to its flavor and aroma?

    <p>&gt;100</p> Signup and view all the answers

    Which of the following factors can affect the flavor of fruits and vegetables?

    <p>Genetics and environment</p> Signup and view all the answers

    What happens to the synthesis of aroma volatiles during the ripening process?

    <p>It increases dramatically</p> Signup and view all the answers

    How does the time between harvest and eating affect the flavor of fruits and vegetables?

    <p>It decreases the flavor</p> Signup and view all the answers

    What can cause off-odours in fruits and vegetables during the postharvest period?

    <p>Fermentative metabolism</p> Signup and view all the answers

    What is the difference between the shelf-life of flavor and appearance in fruits and vegetables?

    <p>Appearance shelf-life is longer</p> Signup and view all the answers

    Study Notes

    Factors Affecting Taste and Quality

    • Different cultivars exhibit varied taste profiles influenced by genetic and environmental factors.
    • Cool temperatures slow down the filling process of banana fruit, impacting sweetness and texture.
    • In citrus fruits, potassium nutrient levels increase acidity, affecting flavor.
    • Internal dryness in Imperial mandarins is primarily caused by water stress or environmental conditions.
    • Juice sacs in mandarins suffering from internal dryness can become shriveled, leading to poor texture and taste.

    Temperature Management

    • Postharvest temperature management does not include liquid nitrogen as a method.
    • Optimal temperature for chilling insensitive produce is typically around 0°C to 5°C.
    • Regions with warmer climates are more likely to have chilling sensitive produce, such as tropical and subtropical areas.
    • The arbitrary threshold temperature distinguishing chilling sensitive from insensitive produce is 10°C.
    • Factors not part of the transport cold chain include padding materials that don’t contribute to insulation.

    Organic Acids and Storage

    • Organic acids like citric and malic acids are stored in the vacuole of fruits and vegetables, impacting flavor and preservation.
    • Damage to the tonoplast can lead to the leakage of compounds from the vacuole, negatively affecting fruit quality.

    Ethylene Management

    • Ethylene absorption is achieved using methods such as active packaging to slow down ripening.
    • Fruits like tomatoes and avocados benefit from ethylene treatments for uniform ripening.
    • 1-Methylcyclopropene (1-MCP) is a common ethylene inhibitor used to delay ripening and fruit drop.
    • Ethylene's concentration over 0.1 µL/L can detrimentally affect the shelf-life and quality of produce.
    • Continuous systems utilizing ethylene scrubbers are being integrated into active packaging solutions.
    • Aminovinylglycine (AVG), marketed under the trade name ReTain, delays ripening and drop in certain fruits.

    Pigmented Phytochemicals

    • Chlorophyll contributes to the green color in plants.
    • Carotenoids, including beta-carotene, cause red/orange pigmentation.
    • Xanthophylls are responsible for the yellow coloration in fruits.
    • Anthocyanins create red, mauve, blue, and purple hues in various plant tissues.

    Ripening and Quality Changes

    • Yellowing of bananas during ripening is attributed to the breakdown of chlorophyll and other pigments.
    • Enzymatic browning in fruits and vegetables is triggered by polyphenol oxidase activity.
    • Transportation damage in fruits and vegetables is commonly linked to mechanical impacts and bruising.
    • The unique shape of certain fruits, like avocados, complicates their postharvest handling.

    Structure and Texture

    • Firmness and texture in fruits and vegetables are closely associated with cell wall composition and integrity.
    • Primary cell walls are composed of cellulose, hemicellulose, and pectin.
    • Enzymatic and mechanical processes modify cell wall structure during ripening, influencing texture.
    • Water loss in produce during storage leads to wilting and decreased quality, impacting visual and taste attributes.

    Flavor and Aroma

    • Two main factors dictating fruit flavor include sugar and acid composition.
    • Gas chromatography-mass spectrometry (GC-MS) analyzes volatile compounds, providing insights into ripe fruit flavor.
    • Diacetyl contributes buttery notes, while furaneol adds sweet, caramel-like flavors to fruits.
    • Ripe fruit may contain hundreds of volatile compounds that contribute to its distinct flavor and aroma.
    • Flavor synthesis processes for aroma volatiles are heightened during the ripening stage.
    • Time elapsed from harvest to consumption can significantly influence the flavor profile of fruits and vegetables.
    • Off-odors during postharvest handling can arise from spoilage processes, impacting overall quality.
    • Flavor tends to have a shorter shelf-life than visual appeal, often deteriorating before appearance.

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    Description

    Test your knowledge on preharvest factors that affect the quality of crops! Explore how genetics, climate, crop nutrition, and agronomy techniques can influence the taste, shape, sweetness, acidity, and photosynthesis of various crops. Gain insights into the impact of preharvest factors on crop quality with this informative quiz!

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