Minimally processed vegetable conservation methods (vegetable technology) // Food engineering

One of the many goals set by food engineering is to extend the shelf life of some foods, in this article I want to mention the technologies used to preserve vegetables and fruits. The demand for food in the world has increased more and more in recent years, which is why technology in food preservation has had to be magnified in its new ways of processing food, and even more in the preservation of food. vegetables, taking into account that these are easier to decompose. This demand for food can be solved in part if it succeeds in developing new techniques that help increase the production of food, in this case vegetables, as long as we take care of the safety of the food.

The extension of the useful life of minimally processed vegetables confronts two basic problems. First the plant tissue is a living tissue that breathes, where many chemical reactions are given to favor the decomposition of it.

Some of the reactions, if left unchecked, can lead to rapid senescence or changes in product quality. Second, the microbial proliferation must be delayed. The growth of pathogenic microorganisms is of interest for the safety of the food, especially with plants of higher pH in contrast to the lower pH of the fruits.

All the above mentioned are the measures that we must have at the time of preserving the vegetables, but with all this, the same question arises:

With what applied technologies can we carry out the procedures named above?

Before being able to mention and explain the applied technologies it is necessary to be able to solve the problems that go hand in hand with certain technical barriers in the control of the physiology of the vegetal tissue and to be able to minimize the microbiological growth being this a critical point for the preservation of fruits and vegetables that are minimally processed.

Among the barriers that must first be overcome before applying any technology is that of distribution, in which once the vegetables already leave for their destination of consumption, they are subjected to a trip where they will be exposed to different external agents that can act negatively, as is the temperature and polluting agents, a situation that makes us reflect on the fact that the distribution of these foods needs to respond to the demands that will surely be required to present these products to the consumer.

Conservation methods to extend the shelf life of minimally processed vegetables can use many of the classic procedures for preserving food. These methods can be: refrigeration; chemical treatment with acidulants, antioxidants, or antimicrobials; packed in modified atmosphere.

In some cases, the reduction of water activity (aw) by removal of moisture would seriously reduce turgor and fresh appearance of minimally processed vegetables. On the other hand, if the reduction of aw is produced by the addition of osmotic agents such as sugar or salt, the resulting product could have undesirable flavor and aroma, different from that of fresh vegetable (Huxsoll, Bolin, 1989).

Freezing conservation tends to cause changes in texture and other characteristics of fresh vegetables. The thermal treatments necessary for the elimination of Listeria monocytogenes, numerous species of Salmonella and elimination of toxin production of C. botulinum could be detrimental to preserve the taste, aroma, texture, color and nutritional quality of the fresh vegetable (Wiley, 1994) .

Treatments with ionizing radiation (irradiation) are frequently proposed as a means to extend the shelf life of fresh fruits and vegetables. Unfortunately, the levels of radiation that are required to prevent microbiological deterioration induce tissue softening (Huxsoll, Bolin, 1989).

Conclusion

Finally, the effectiveness of the treatments used and the applicability of the developed models in a diversity and range of vegetables and fruits should be studied, since not all the foods respond in the same way to the same conditions, food engineering by means of of the study of vegetable technologies provides tools such as laboratories to experiment on some basic vegetables, which we can subject to the same conditions and observe certain variables such as degree of acidity, humidity percentage, microbiological elements among others and of this way to build conservation models for each of the most important minimally processed vegetables in the market.

References consulted:

1. Alzamora, S.M. 1997. Preservation I. Foods preserved by combined factors. In Topics in Food Technology. Mexico.

2. Day, B.P. 1995. Fruits and Vegetables. In Packaging of food in a modified atmosphere. Editions A. Madrid Vicente. Spain.

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