Solid state fermentation in food processing: advances in reactor design and novel applications

GARRO MARISA S; RIVAS FRANCO P; GARRO OSCAR A

Innovative Food Processing Technologies

Elsevier

Lugar: Amsterdam; Año: 2020; p. 165 - 182

Solid state fermentation (SSF) is a process in which microorganisms grow in an environment without free water, or with a very low content of free water. Solid state fermentation has been known since ancient times in Asian and Western countries [1, 2], mainly for food processing. In the SSF, several types of fungi [3], bacteria [4] and actinomycetes [5] have been used for the production of various biological products. Some examples are the fermentation of rice by Aspergillus oryzae to initiate the koji process, the production of cheese with Penicillium roquefortii [4, 6, 7] and the use of yeasts to ferment and rise bread. It is currently used for the production of biomolecules and important products for many industries, including food, pharmaceuticals, textiles, biochemistry and bioenergetics, among others [8]. Lactic acid bacteria (LAB) are used since antiquity to preserve different raw materials. They are found in different vegetable matrices, meats, milks, in the intestinal tract of animals and humans; they intervene in the production of different fermented foods. This is why lactic fermentation is one of the important fermentative pathways in food production processes using both liquid and solid substrate fermentation. They prolong the shelf life of the food avoiding undesirable contamination; they also contribute to improve the texture and the sensory profile of the final product [9]. Bifidobacteria are used principally as health promoting or probiotic components in different fermented functional foods. They can contribute to the health status of humans. They have an important capability to utilize a wide range of complex oligosaccharides, synthetize vitamins from B group, and produce enzymes with potential importance in fermentation processes [9]. Most of these works are based on liquid fermentation (submerged fermentation SMF) and there are few works in SSF. However, in the last few years, SSF is being investigated for other applications. The importance of SSF was almost ignored in Western countries. However, in the last two decades, SSF has attracted attention due to several biotechnological advantages, such as greater fermentation capacity, greater stability of the final product, less substrate inhibition and a cost-effective technology [10-12]. This is the reason that works have been published that addresses the issue of fermentation in solid substrate from different points of view. Thus, there are several works that using statistics and analysis tools applying response surface have tried to optimize different fermentation parameters for the design of suitable starters to produce healthy food (e.g. using soybeans, meat, etc). It is also important to describe the generalities of SSF, although numerous reviews have been published in recent years.