Pontonio E, Dingeo C, Gobbetti M, Rizzello CG.

Front Microbiol. 2019 Mar 19;10:561. doi: 10.3389/fmicb.2019.00561. eCollection 2019.

 Abstract

Although recognized as important sources of functional compounds, milling by-products are often removed from the cereal kernel prior milling process. Indeed, the high presence of fiber in bran and the co-presence of lipids and lipase in germ are often considered as downsides for breadmaking. In this work, Lactobacillus plantarum T6B10 and Weissella confusa BAN8 were used as selected starters to ferment maizemilling by-products mixtures made with heat-treated or raw germ and bran. The effects on the biochemical and nutritional features as well as the stability of the milling by-products were investigated. Lactic acid bacteria metabolisms improved the free amino acids and peptides concentrations and the antioxidant activity and caused a relevant phytic acid degradation. Moreover, fermentation allowed a marked decrease of the lipase activity, stabilizing the matrix by preventing oxidative processes. The use of fermented by-products as ingredients improved the nutritional, textural and sensory properties of wheat bread. Fortified breads (containing 25% of fermented by-products) were characterized by a concentration in dietary fiber and proteins of ca. 11 and 13% of dry matter, respectively. Compared to the use of the unfermented ones, the addition of pre-fermented by-products to bread caused a significant increase in protein digestibility (up to 60%), and a relevant decrease of the starch hydrolysis index (ca. 13%). According to the results, this study demonstrates the potential of fermentation to convert maize bran and germ, commonly considered food wastes, into nutritive improvers, meeting nutritional and sensory requests of modern consumers.

See: https://www.ncbi.nlm.nih.gov/pubmed/30941115

Figure 1. Boxplot showing the functional (A) and pro-technological (B) characterization of 100 strains of lactic acid bacteria belonging to the species Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus helveticus, Lactobacillus farciminis, Lactobacillus nantensis, Lactobacillus plantarum, Lactobacillus rossiae, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, Weissella cibaria, Weissella confusa, Leuconostoc citreum, and Leuconostoc mesenteroides of the Culture Collection of the Department of Soil, Plant and Food Science of the University of Bari, Italy and isolated from raw or spontaneously fermented wheat, hemp, hop, quinoa, wheat germ and bran. The increase (%) of TFAA concentration, phytase (PA) and radical scavenging (RSA) activities in wheat, hemp, hop, quinoa, wheat germ and bran (DY 200) singly inoculated with the strains and fermented for 24 h at 30°C, compared to a not inoculated dough incubated in the same conditions were considered as functional features. Panel B displays the boxplot of the acidification (A_A, pH; λ_A, h) and growth (A_G, log 10 cfu/g; λ_G, h) kinetics parameters of the strains in the above-mentioned conditions, respectively. The top and the bottom of the box represent the 75th and 25th percentile of the data, respectively. The top and the bottom of the bars represent the 5th and the 95th percentile of the data, respectively.