Preservation techniques and their effect on nutritional values and microbial population of brewer’s spent grain: a review

Abstract

The most prevalent by-product produced by the brewery factory is brewer's spent grain (BSG). A total of 70%, 10%, and 20% of the BSG produced are used for animal feed, biogas production, and landfills, respectively. Feeding wet brewery spent grain can avoid the cost of drying. Wet brewery spent grain is used as a replacement for forage in the diets of animals. The high moisture content and ease of deterioration of wet brewery leftover grain as a fresh feed are drawbacks (3–5 days). BSG is provided as a low-cost feed despite its greater perishability and microbiological instability. There are two significant challenges brought on by the BSG's higher moisture content (80%). First, transportation is expensive. Second, the abundance of proteins and polysaccharides in BSG promotes microbial development and deterioration. Therefore, these problems can be solved by utilizing various preservation methods, including drying (solar, freeze, and oven drying), freezing, ensiling (both alone and in combination with other animal feeds), and additives (Silo-King GPX preservatives, xylanase, carbohydrase (econase) and protease (alcalase), urea and lime, sodium formate, calcium propionate, formic and propionic acids, acetic acid, NaCl, NaOH, HCl, and H2SO4).

Impact of Storage Temperature on Microbial Diversity and Probiotic Effect of Liquid Brewers’ Yeast

“…Feeding animals on fresh LBY could avoid the cost of preservation, such as drying, and ensure quality and safe feed [24]. Value chain actors' lack of storage and conservation facilities, especially in the developing world, is the leading cause of LBY spoilage [25].…”

Sustainable Particleboards Based on Brewer’s Spent Grains

“…BSG is classified as a lignocellulosic material and contains hemicelluloses (19–40%), cellulose (10–25%), lignin (11–27%), protein (14–30%), and polysaccharides such as starch, as well as less abundant amounts of non-polymeric components like phenolic compounds, alfa amino acids, fatty acids, vitamins, and minerals [ 46 , 47 , 48 ]. The high moisture content and chemical composition of BSG (mostly carbohydrates and proteins) make it susceptible to microbial spoilage and chemical deterioration by fungi, yeasts, and aerobic bacteria [ 13 , 49 ]. This limitation restricts its transportation from the brewery to short distances, although drying at the plant would facilitate its distribution beyond its production area.…”

Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations

“…A major use of BSG is animal feed because of its high contents of fats, proteins, and minerals [ 25 ]; it has also been used as food additives and a source of amino acids and sugar [ 26 , 27 ]. The high moisture content in BSG expedites its deterioration, which has posed a huge challenge to its preservation and transportation [ 28 ]. The color and offensive smell of its deteriorated form is a problem to the environment and can be an issue in its utilization as food supplements.…”