UPMSP Class 12 Food & Fruit Preservation - Code 202 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Water activity (aw)

Ratio of the vapour pressure of water in a food to that of pure water at the same temperature. It predicts microbial growth better than moisture content; most bacteria need aw above 0.90.

Climacteric fruit

Fruit that continues ripening after harvest with a burst of respiration and ethylene production, such as banana, mango, tomato and apple. Non-climacteric fruit like citrus and grapes do not.

Enzymatic browning

Brown discolouration of cut fruit and vegetables caused by polyphenol oxidase acting on phenols in the presence of oxygen. Blanching, sulfites, acid or oxygen exclusion prevent it.

Intrinsic spoilage factors

Properties of the food itself that govern which microorganisms grow: pH, water activity, nutrient content, oxidation-reduction potential and naturally occurring antimicrobial compounds.

Hurdle technology

Combining several mild preservation factors such as low pH, reduced water activity, chilling and preservatives so that no single treatment must be severe, preserving sensory quality.

Commercial sterility

Condition in which a food is free of viable microorganisms capable of growing under normal storage conditions, including heat-resistant spores of public health concern. It is not absolute sterility.

Blanching purpose

Hot water or steam treatment that inactivates enzymes, removes tissue gases, fixes colour and shrinks tissue before freezing or drying. It is not a sterilization process.

Aseptic processing

Separate sterilization of food and packaging followed by filling and sealing in a sterile environment, allowing products such as UHT milk to be stored without refrigeration.

Pectin gel formation

Jam and jelly set requires pectin, acid at about pH 3.0 to 3.5 and sugar at roughly 60 to 65 percent soluble solids, which together form a three-dimensional gel network.

Clarification of juice

Treatment of extracted juice with enzymes, fining agents or filtration to remove pectin and suspended solids, producing a clear juice. Pulp juices skip this step.

TSS and Brix

Total soluble solids measured in degrees Brix, mainly sugars. It is the standard quality index for juices, squashes, jams and tomato products.

Fruit beverage classes

Products distinguished by fruit content: 100 percent juice, nectar with roughly 25 to 50 percent fruit, and squash or cordial that is diluted before drinking.

D value

Decimal reduction time: the time at a given temperature needed to reduce a microbial population by 90 percent, or one log cycle. It measures heat resistance.

z value

Temperature change in degrees Celsius required to change the D value tenfold. It describes how strongly the heat resistance of an organism depends on temperature.

F0 sterilizing value

Equivalent minutes of heating at 121 degrees Celsius with a z value of 10 degrees. A minimum F0 of 3 minutes is used for low-acid canned foods.

Flat sour spoilage

Canned food spoilage by thermophilic Bacillus species that produce acid without gas, so the can stays flat while the product turns sour.

Retort venting

Removal of air from a pressure retort by steam before the process begins, ensuring uniform steam temperature and preventing cold pockets around the cans.

Freezing rate and crystals

Fast freezing produces many small ice crystals inside cells, preserving texture. Slow freezing forms large extracellular crystals that rupture cells and cause drip loss on thawing.

Controlled atmosphere storage

Storage in which oxygen is reduced, typically to 2 to 3 percent, and carbon dioxide raised to slow respiration and extend shelf life of fruits and vegetables.

Freezer burn

Dry, discoloured surface patches caused by sublimation of ice from unpackaged frozen food. Prevented by moisture-proof packaging and stable freezer temperature.

Chilling injury

Damage to tropical fruits such as banana and mango kept below about 10 to 13 degrees Celsius, shown as pitting, browning and failure to ripen.

Falling-rate drying

Drying stage in which internal moisture diffusion controls the rate, so the curve flattens. Surface evaporation no longer limits the process.

Case hardening

Defect in which rapid surface drying seals the outer layer of a food while moisture remains trapped inside, slowing drying and reducing quality.

Freeze drying

Lyophilization: freezing the product then sublimating ice under vacuum. It best preserves shape, flavour and nutrients but is slow and expensive.

Osmotic dehydration

Partial removal of water by soaking food in concentrated sugar or salt solution, drawing water out through the cell membrane before further drying.

Sodium benzoate

Chemical preservative most active in acidic foods below about pH 4.5, inhibiting yeasts, moulds and some bacteria. Permitted limits apply and it must be declared on the label.

Potassium sorbate

Preservative effective over a wider pH range than benzoate, mainly against yeasts and moulds. Commonly used in beverages, cheese and baked goods within permitted limits.

Lactic acid fermentation

Conversion of sugars to lactic acid by Lactobacillus and related bacteria, lowering pH and preserving products such as sauerkraut, pickles and yoghurt.

Class I preservatives

Naturally occurring preservatives permitted without strict limits, including salt, sugar, vinegar, honey, spices and edible oils. Class II covers chemical additives such as benzoates.

HACCP seven principles

Hazard analysis, determination of critical control points, critical limits, monitoring, corrective actions, verification and record keeping. It is a preventive food safety system.

Modified atmosphere packaging

Packaging in which the internal gas mixture is altered, usually low oxygen with raised carbon dioxide, to slow respiration and microbial growth and extend shelf life.

Break-even quantity

Output at which total revenue equals total cost, calculated as fixed cost divided by the difference between selling price per unit and variable cost per unit.