Fruit and Vegetables Flashcards
Definition of fruit and vegetables
Fruit: fresh part of the plant
Vegetable: part of the plant served raw
General properties of fruits & vegetables
Fruit: acidic and sugary, grouped into divisions depending on structure and composition
Vegetable: derived from various parts of plants, huge genetic diversity
General composition of fruits & vegetables
Depends on various components
- high in water
- low in protein and fat
- good source of digestible and fermentable carbohydrates
- good source of vitamins and minerals
Describe structure of a plant cell
Vacuole - composed of water and substances in it
Chloroplasts & Mitochondria - energy conversion through photosynthesis and cellular respiration
Leucoplasts - stores starch as an energy source
Nucleus - controls reproduction and protein synthesis
Describe 4 plant tissues and their functions
Dermal tissue - layer of protective tissue
Vascular Tissue - used to transfer food and water
Supporting tissue - parenchyma, collenchyma & sclerenchyma
Storage tissue - parenchyma cell tissue making up most of the edible portion of F & V
Understand turgor & texture
Tugor: rigidity of plant cells from being filled with water
Texture: affected when the plant tissue is damaged or killed by storage freezing or cooking
Know about the other cell constituents affecting texture
Cellulose - major component of cell walls
Hemicellulose & Lignin - cells walls thicken as the plant ages
Pectin substances - glue in the cell to hold plant cells to one another
Starch - granules of starch molecules within cells swell upon heating causing the cell to swell and become firm and plump
Understand the major groups of pigments in fruits and vegetables
- Chlorophylls - contain chloroplasts (green)
- Carotenoids - fat soluble & pre cursor for vitamin A (yellow - orange - red)
- Anthocyanins - belong to flavanoid group (purple, red and blue)
- Anthoxanthins - colour depends on pH (violet or blue).
- includes Tannins (colourless but turn dark when reacted with metal ions)
Function of Elaioplasts
Storage of lipids and oils
Factors affecting F & V production
- soil
- watering and fertiliser requirements
- actual days available to grow and ripen
What is harvesting?
Collecting F & V at the specific time of peak quality in terms of colour, texture & flavour, in order to market them. This can be done by hand or by machine (which affects the quality and quantity)
Respiration and its influence on harvested F & V
- F and V continue to respire after harvest
- influences storage packing and refrigeration requirements
- can cause growth of mould or damaged produce
Difference between ripeness and maturity of F & V
- Ripeness: the optimum or peak condition of flavour, colour & texture
- Maturity: the condition of a F/V when it is picked
Explain climacteric & nonclimacteric with examples
Climacteric = fruits producing ethylene gas during ripening
Nonclimacteric = fruits don’t produce ethylene (- don’t ripen after harvesting) & are ethylene sensitive
Changes to F & V post-harvest
Carbs - starch decreases quickly and sugar increases post harvesting
Pectins - contributes to softening of produce
Organic acids: decrease during storage and ripening (important for fruit)
Post-harvest factors needing consideration during storage
- Temp reduction and maintenance reduces the metabolic activity of produce and spoilage microorganisms
- Use of natural or synthetic chemicals
- Modified atmosphere (humidity)
Define senescence
Quality decline in stored respiring F & V after harvesting
eg. Strawberry going white, to red, to gross
Describe the processing of fruits (canning, freezing, juicing)
Canning
- harvesting
- fruit sorted and washed by machine
- cans are filled with fruit, followed by addition of syrup or juice
- cans are sealed and cooked
- cans are cooled and sold to consumers
Frozen
- after initial preparations, bags are filled with fruit and syrup is then added
- packages seals and frozen
Fruit Juice - Extraction - Clarification (clearing) - Deaeration (removal of air) - Pasteurisation/High-pressure processing (HPP) - Concentration - Essence add-back (flavours) - Canning or bottling - Freezing Juices can also be blended or cold pressed by a hydraulic press
Describe the processing of vegetables (canning and freezing)
Canning
- veges are washed and mechanically peeled
- put into cans or jars
- brine is added
- cans are sealed and cooked
- cooled and sold to consumers
Frozen
- veges are washed, cut and blanched / pre cooked to ensure they keep their natural colour and flavour
- veges are frozen and then bagged
