Chapter 20 - Fruit quality control, evaluation, and analysis

Abstract

Harvested fresh citrus fruit when marketed must meet stringent quality norms for external as well as internal quality attributes. Market is highly competitive and based on consumer demand. Moreover, the meaning and perception of quality is different for different people. The fruit quality could be defined as the combination of fruit attributes or characteristics that have significance in determining the degree of consumer acceptance. This means that better the quality, the higher the rate of acceptance and vice-versa. In today’s world of quality conscience consumers, the quality of fresh citrus fruit is very important for successful trade. For the sake of quality control, certain standards are fixed. Based on these standards, quality inspectors judge the quality and decide its grade, utility, and marketability. Quality evaluation and control is also essential for deciding fruit price. Quality control can take place at various stages of fruit handling and marketing. In fact, it starts in the field. Quality attributes can be evaluated by both subjective and objective methods. The objective methods are precise and involve the use of instruments, while subjective methods make use of human senses. Quality evaluation methods could also be grouped as destructive and nondestructive depending on whether fruit is destroyed (cut or punctured) during analysis or remains intact. The advantage of nondestructive methods is that they can be used when fruit is still attached to the tree and quality can be monitored. Moreover, nondestructive methods can be used after harvest to make sure that every fruit sent to the market meets the quality norms, in contrast to the destructive method, in which a representative sample is taken and it is lost during analysis. (Thus it cannot be marketed.) Most of the conventional methods of quality evaluation are destructive. The quality attributes and evaluation methods could be grouped into three categories—physical, chemical, and physiological—on the basis of analytical process and principals involved. Microbial quality is evaluated in processed citrus fruit, but physiological attribute evaluation is not done in processed fruit. These are mostly objective methods, while the sensory evaluation is subjective and based on the response of human senses to external and internal fruit quality. For example, the external quality parameters are mostly related to the senses of vision and touch as influenced by the fruit appearance. As many as 12 quality factors affect appearance. These parameters are: (1) rind color, (2) rind texture, (3) discoloration, (4) blemishes (scars resulting from wind or twig rubbing, scab, scales, melanose, stem-end injury, or any other insect damage), (5) bruises resulting from transport or other factors, (6) oleocellosis, (7) oil-spray injury, (8) hailstorm injury, (9) sunburn, (10) creasing, (11) rind breakdown, and (12) puffing.