What are the quality attributes of foods ?
The term quality attributes includes all the factor that influence product’s value to the consumer. Quality attributes can be positive or negative. Negative attributes includes spoilage, contamination, discoloration, off odor etc. while positive attribute includes safety, nutrition, flavor, color, texture, suitability of processing etc. quality attributes of food can be well described by following classification.
- Quantitative attribute: It is important from standpoint of both traders and ultimate consumers. It is expressed as proportion of ingredients net weight, drain weight etc.
- Hidden attribute: It implies suitability of product from standpoint of health and which consumers cannot evaluate through their own sense. It includes safety and nutritional factors.
- sensory attributes: It is based on consumer’s preferences perceived by their senses. This includes appearance, kinesthetic factor and flavor factor.
Factor Influencing sensory attributes
It is an eye appeal judged by sense of sight. Such as,
a) Size and shape wholesomeness: It can be easily perceived by eyes. However, for accuracy and standards, devices such as screen, scale, micrometer etc. are used. For shape, weight/volume ratio, symmetry, length/width ratio, curvature area etc. are measured.
b) Size and shape wholesomeness: It can be easily perceived by eyes. However, for accuracy and standards, devices such as screen, scale, micrometer etc. are used. For shape, weight/volume ratio, symmetry, length/width ratio, curvature area etc. are measured.
c) Defects, damage, extraneous matter: Defects are imperfections due to presence of something unwanted. Defects may include
- Insect damage or injury (bruising, crushing)
- Extraneous matter or foreign matter. Extraneous matter might be harmless but not part of edible portion. Such as eyes in canned pineapple slices
- Deformed shape of fruits and vegetables (due to environment or genetic factor) or other processed food (due to fault in processing).
Spectral: This includes color, gloss, transparency, turbidity etc. color and gloss are attributed to spectral distribution of light. Transparency, haziness and turbidity is attributable to absorbance or transmittance of light by the material.
Consistency: This includes viscosity, gel flow and spread. Major quality attributes with food such as ketchup, juice, cream, jam marmalade, syrups etc. viscosity is resistant force to deformation when subjected to shearing force. Measurement of viscosity not only indicate consistency of final product but also quality control tools applied for raw material and during processing to obtain desired final product.
It is judged by sense of touch such as hand feel (firmness, softness, juiciness, grittiness) and mouth feel (chewiness, fibrousness, grittiness, mealiness, stickiness). Kinesthetic attributes or texture is the way in which structural components of food are arranged in micro or macro structure and the external manifestation of these structure. It includes qualities of food that can be felt with tongue, palate or teeth. The range of texture is considerable and departure from expected texture is a quality defect. Take for example; apples are expected to be firm, mango and plum to be soft, sweet corn to be juicy and potato chips to be crisp.
Some important kinesthetic parameters are
|1||Hardness||Soft, firm, hard|
|2||Cohesiveness||Crumby, crunchy, brittle, tender, chewy, tough, short, mealy, pasty, gummy|
|3||Adhesiveness||Sticky, tacky, gummy|
|4||Particle size||Gritty, grainy, coarse|
|5||Shape and orientation||Fibrous, cellular, crystalline|
|6||moisture||Dry, soggy, moist, wet, watery|
Physical instruments can also be applied to simulate and measure the sensation which the consumer experiences (kinesthetic attributes) such as texture analyzer, viscometer etc.
It Is judged by sense of taste and smell. It includes sense of odor such as fragrance, acid and burnt, sense of taste such as sweet, sour, salty and bitter and sense of off-flavor such as enzymatic, physiological, chemical, contamination, overcooked etc. Flavor attributes are evaluated by consumers with the sense of taste and smell. The term flavor indicates four basic taste and aroma received through tasting. There are four basic taste and are sensed by different receptor sites of tongue.
|tip of tongue|
|Salt:||tip and edge of tongue|
|Sour:||edge of tongue|
|back of tongue|
Desirable flavor in food is a positive quality attributes which can be retained in food by
- Prevention of loss of desirable flavor during heat treatment, handling, transport and storage.
- Avoidance of development of undesirable flavor. Example, oxidative rancidity in fat and oil and metallic flavor in canned products.
- Development and preservation of desirable flavor as in roasting coffee bean, baking bread, aging wine etc.
- Fortification of food with natural flavors that are lost during processing.
Name : Pratiksha Shrestha
Ms. Shrestha holds masters degree in food engineering and bioprocess technology from Asian Institute of Technology (AIT) Thailand. She is currently working for Government of Nepal at Department of Food Technology and Quality Control (DFTQC), Kathmandu. She is also a teaching faculty in College of Applied food and Dairy Technology (CAFODAT) affiliated to Purbanchal university, Nepal.