30 Questions
What is the primary purpose of blanching in food processing?
To inactivate natural enzymes that cause discoloration and off-flavors and aromas
What is the ideal temperature for blanching vegetables in hot water?
88°C (190°F)
What is the result of removing water from vegetables during dehydration?
Reduced volume and weight
What is the purpose of rapid cooling after blanching?
To retain better quality
Which of the following is NOT a method of dehydrating vegetables?
Boiling
What is a common practice for roots and legumes after harvesting?
Bulk handling and grading
What is the effect of blanching on microorganisms in vegetables?
It reduces the number of microorganisms
Why are treatments necessary for some vegetables?
To extend their shelf life
What is the purpose of washing and waxing some vegetables?
To improve their shelf life and attractiveness
What is the benefit of modified-atmosphere packaging?
It slows the respiration rate and senescence of cut vegetables
What is the atmosphere composition in modified-atmosphere packaging?
High in carbon dioxide and low in oxygen
What is the purpose of vacuum packing and modified-atmosphere packaging?
To increase the shelf life of vegetables
What treatment helps to preserve the texture of potatoes during the reconstitution process?
Precooking and cooling
What is the primary function of sulfite in dehydrating potatoes?
Aiding heat transfer and acting as a blanching agent
Why is canning a suitable method for food preservation in developing countries?
It is particularly useful in areas where refrigeration is limited or nonexistent
What happens to the containers during the canning process?
They are sealed while hot
What is the main purpose of the heat treatment during canning?
To ensure the destruction of bacteria spores
Why is the industry searching for sulfite replacements?
Due to consumer concerns about allergies
What is a limitation of freeze-drying in vegetable products?
It is too expensive
What is a characteristic of dehydrated potato granules?
They have a pasty texture
What is the purpose of air-lift drying in dehydrated potato granules production?
To bring the product to 10–13 percent moisture
What is the difference between dehydrated potato flakes and granules?
Flakes have a mealy texture, while granules have a pasty texture
What is used to dry dehydrated potato flakes to final moisture content?
Steam-heated drum drier
What is the texture of mashed potatoes made from dehydrated potato flakes?
Mealy
What is a possible cause of bulged cans after long periods of storage?
Inadequate heat processing
What is the nutrient most susceptible to destruction in canning?
Vitamin C
What is the process of aseptic canning also known as?
High-temperature–short-time (HTST) processing
What is a characteristic of frozen foods?
Outstanding quality and high nutritive value
What is a possible consequence of consuming canned vegetables with bulged cans?
Botulism
Why may some canned vegetables have inferior quality and less nutritive value?
Severe heat treatment
Study Notes
Dehydration
- Freeze-drying produces high-quality food, but it is costly and rarely used for vegetables
- Dehydration is an old method of preserving food, removing water to reduce volume and weight, and aiding storage and transportation
Potato Products
- Instant potatoes are a common dehydrated product, used in restaurants and institutions
- Dehydrated potato granules have high bulk density, easy to handle, but produce mashed potatoes with a pasty texture
- Dehydrated flakes, on the other hand, produce mashed potatoes with a mealy texture, comparable to freshly prepared mashed potatoes
- Air-lift drying is used for granules, while steam-heated drum drying is used for flakes
Processing Vegetables
- Harvesting roots and legumes often involves machine-based harvesting, with some sorting and grading in the field or at collection stations
- Bulking is common, with few additional preparation steps before distribution
- Treatments may be necessary to prevent microbial spoilage, insects, and small animal invasion
- Washing, sorting, grading, cutting, and packaging into retail-size containers are steps taken for convenient foods
Blanching
- Blanching involves heating vegetables in hot water or steam to inactivate natural enzymes, reduce microorganisms, and make them limp for easy packing
- Blanching also serves to remove harsh flavors in some vegetables
Dehydration Methods
- Many machines are available for dehydration, including tunnel drying, vacuum drying, drum drying, spray drying, and freeze drying
Canning
- Canning is a major food-processing method, particularly useful in developing countries where refrigeration is limited
- Properly processed canned vegetables can be stored at room temperature for years
- Aseptic canning, or high-temperature–short-time (HTST) processing, is a superior method that avoids slow heat penetration and produces high-quality products
Learn about the different steps involved in handling and preparing vegetables for distribution, including sorting, grading, and treatments to prevent spoilage. This quiz covers the process of handling roots, legumes, and other vegetables that require long-term storage.
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