Evaluation of minimally processed apples with application of edible films through biospeckle

Abstract

The search for practical eating has been increasing among consumers. Thus, minimally processed (MP) foods, which are fresh, previously cut, washed, sanitized and packed products, may be covered with films so as to keep their quality, reducing the deterioration processes. This paper aimedto evaluate the quality of fresh cut apples covered and uncovered with an edible film, through conventional techniques and through biospeckle which is an alternative method of quality evaluation. That analysis was correlated to methods, such as Hunter L*, a* and b* parameters. Total soluble solids (TSS), total titratable acidity (TTA), respiration rate and pH, as well as the biospeckle optical technique, were measured through the calculation of the moment of inertia (MI). Apples were sorted into three sets: samples with sodium alginate edible film, samples with pectin edible film and control samples with no film. In optical tests, a diode laser with a wavelength of 632 nm, a digital camcorder, a computer with image processing and statistical software were used. Results showed that both edible films (alginate and pectin) presented lower MI values, indicating the decrease of the biological activity. The conservation of the products observed through the reduction of biological activity promoted by the films keeps the apple quality for a longer period of time. The biospeckle technique can be related to the intensity of the biological activity of the vegetable tissue.