Solid-state fermentation of post- harvest wastes of Solanum tuberosum and a microbial preparation

Abstract

With the objective of studying the solid -state fermentation of post - harvest wastes of S. tuberosum and a microbial preparation, an experiment with a completely randomized design with factorial arrangement (3x3) and three repetitions was carried out. The factors were temperature (20, 25 and 30 ºC) and fermentation time (0, 24and 48 h). Measurements of the indicators pH, ammonia, organic acids, crude fiber, crude protein and true protein, dry matter, ash and microbiological analysis were performed. The results of the microbiological analysis carried out on the fermentation of postharvest wastes of S. tuberosum shows a high concentration of lactic acid bacteria (LAB) and the low pH found eliminated the pathogens agent(p <0.0001). In the solid fermentation with the microbial preparation, low propionic acid and ammonia values were recorded at 20 ºC and an increase in lactic acid (p <0.0001). There is a marked effect of temperature on humidity during fermentation. Low fiber and DM values were recorded. True protein increased at 24 h by 2.7 percentage units at 25 ºC in correspondence with the microbial concentration of mesophilic bacteria (5.5x107 CFU/mL), LAB (6.1x107 CFU/mL) and yeasts (1.3x104 CFU/mL). It is concluded that the solid state fermentation of post- harvest wastes of Solanum tuberosum and a microbial preparation with lactic activity favors this process and other formulations with drying and fibrous material should be studied for an effective ensiling process of the final product.
Key words: lactic bacteria, agro-industrial wastes, organic acids