Arguably, consumer preferences are currently moving towards easily prepared food, less severely processed food (vitamins and nutrients preserved), natural food (without preservatives and other artificial additives), healthy products (functional food, low in fat, less salt), and more secure.
According to Spanish research company AZTI, research and development in the area of food has been directed in two main directions: towards non-thermal treatments, such as high pressures, pulsed light, electric pulses, irradiation, use of modified atmospheres and biopreservatives, and towards improved thermal treatments, such as ohmic warming or microwaves.
AZTI is currently working on two methods: pulsed light and vacuum cooking. Pulsed light involves applying white light "pulses" or flashes of high intensity (approximately 20,000 times more intense than the solar light on the earth surface, between 0,001 and 50 J/cm2) and very short duration (less than a millisecond) on the food surface.
Scientists at AZTI, who tested the technology on fresh hake fillets (Merluccius merluccius), found a reduction in the recount of aerobics, mesophilics and psicotrophics, as the number of flashes increases, obtaining the destruction of the 90 per cent from 25 flashes on - equal to a total energy of 38 J/cm2. No sensorial alteration was observed in the treatments.
The researchers claim that this is a very versatile technology that can be applied in lipids, such as in water, juices or translucent liquid products that allow the passing of the light. They added that further research involving the pulse light technology on solid products is currently underway in France and Belgium.
The vacuum cooking technology consists of vacuum packing the pre-cooked product. The thermal treatment is usually under 100 ºC (equivalent to pasteurisation), followed by a fast cooling phase until it reaches an adequate temperature to be kept in the refrigerator. AZTI researchers believe that this technique presents a clear advantage from the organoleptic and nutritional point of view when compared to conventional thermal treatments. In addition, they claim, there are other commercial advantages: the commercial life is increased (20-21 days), cooking techniques are reduced (in fish products up to 10 per cent) and a variety of menus can occur simultaneously (as they are packed, they can be warmed in the same oven without mixing the smells). The scientists add that the soft treatment of vacuum cooking is enough to solve the problem of non-sporulated psicotrophic pathogens, such as Listeria monocytogenes.
AZTI obtained good results with refrigerated precooked dishes of fish products with 15 and 20 days of duration, such as refrigerated cooked seafood, mackerel and jack mackerel in different sauces. The precooking process of fish improves its appearance and avoids the later exudation of the final product. The independent processing and subsequent addition of sauce and fish before the pasteurisation significantly improves the taste and the global impression, claim the scientists.
They add that the use-by date of the vacuum cooked products is limited to 28 days due to the possible presence of resistant pathogen micro-organisms, mainly C. Botulinum, and to eventual breaking of the cold chain that is sometimes produced in the distribution and sale.