Partly copied from ‘Sensing taste of fruits and vegetables using near infrared (NIR) Technology’. M.Sc. Thesis by Nawaf Abu-Khalaf
Tito is a lover of fruits. I really do love my fruits. Back in the university, I recall my closest friend TKB Charles often called me a monkey because of how much I ate bananas, while serving in the youth corps, another friend exclaimed on the number of garden eggs I eat, now my closest pal and colleague as a graduate student calls me ‘the cucumber monger’. You need to see me in my elements. Fruits are good but many times you buy something that looks good but eventually find it’s no good. Your plight may be over.
At present time, the consumption, marketing and grading of fruits are based on their external aspects. Fruits are stored and marketed visually, manually or automaticallyon the basis of size, color and surface defects. However, internal attributes like dry matter content, total soluble solids contents (refractive index), juice acidity, firmness, etc., are important. Most instrumental techniques to measure these properties are destructive, and involve a considerable amount of manual work.
In recent years, research has been focused on the development of non-destructive measurement techniques for quality attributes of fruits (mainly: apples) and vegetables such as pH, sugar content and firmness. NIR spectroscopy is one of such techniques. The advantages and major disadvantages of this technique are:
Its fast execution;
More than one parameter may be estimated at the same time (by using
multivariate data analysis technique);
Simplified sample preparation;
Ease of implementation in process control and grading system; and
Lack of chemical pollution.
NIR spectrum is not easy to interpret, since most models are black box
The equipment is expensive; and
New calibration curve is needed for each variety to obtain good results.
Despite these disadvantages, NIR spectroscopy is the most appropriate technique in terms of speed of assessment and cost at the present time.
In Japan, there are a number of NIR systems in commercial operation for the on-line grading of fruit according to sweetness. There were many contributions using NIR spectroscopy in the field of non-destructive quality assessing like pH, sugar content, firmness, texture parameters, optimal picking date, light penetration of NIR in fruit and bruises.
Taste is also an important internal quality parameter of agricultural commodities, an issue not often discussed in literature. Fruit’s taste is the major asset of fruit quality. The feasibility of using NIR spectroscopy for detecting taste of fruits, based on known NIR ability to predict SSC, acidity and chemicals components.
A non-destructive NIR technique (reflectance mode) for sensing taste of fruits and vegetables may be greatly appreciated among package storage houses, and great store markets for grading fruits according to their taste quality. Since, in practice, apples (for example) are sold in batch and the internal quality of the whole batch is estimated by the average of the lab values of sample sub set. With this method (NIR technology), all apples could be controlled and the consumers will know the taste of what they’re buying.
How Tasty does that sound? Anyway, you should try this for taste: a blend of apples, oranges (remove the seeds, please) and bananas.