Food Ingredients for the Future: In-Depth Analysis of the Effects of Lactic Acid Bacteria Fermentation on Spent Barley Rootlets

Abstract

Repurposing by-products to alternative applications has become a vital part of food research. Barley rootlets (BRs) are a side-stream of malting and brewing industries. This study focuses on processing BRs into food ingredients, using fermentation with five lactic acid bacteria (LAB) as a valorisation technique. The strains used were Lactiplantibacillus plantarum FST 1.7, Lactobacillus amylovorus FST2.11, Weissella cibaria MG1, Leuconostoc citreum TR116 and Limosilactobacillus reuteri R29. The influence of fermentation on sugar/FODMAP/acid compositions and microbial metabolites in BRs was analysed. A variety of techno-functional properties were also evaluated. Results showed BRs were a suitable substrate for LAB, particularly for Lactiplantibacillus plantarum FST 1.7 and Lactobacillus amylovorus FST2.11. Sugar, acid and the FODMAP composition of the fermented BRs demonstrated various traits imparted by LABs, including high mannitol production from Leuconostoc citreum TR116 and Limosilactobacillus reuteri R29. Limosilactobacillus reuteri R29 also produced fructans using BRs as a substrate. A techno-functional analysis of BRs showed a significant reduction in α-amylase activity post sterilisation and fermentation. Fermentation reduced water-binding capacity and significantly increased oil-binding capacity. The LAB used displayed great potential in improving the functionality of BRs as a food ingredient while also showcasing LAB fermentation as a viable processing aid for BR valorisation.

From Waste to Taste: Application of Fermented Spent Rootlet Ingredients in a Bread System

“…Along with BR, bread recipes also included instantaneous freeze-dried yeast (Puratos, Groot-Bijgaarden, Dilbeek, Belgium); granulated sugar (Siúcra, Dublin, Ireland); salt (Glacia British Salt Limited, Cheshire, UK); sunflower oil (Musgraves, Cork, Ireland); and regular faucet water. The compositional analyses of the BF and BR-UnF are illustrated in Table 2 , with the composition of the BR-UnF previously reported by Neylon et al [ 19 ]. The compositional analysis was carried out externally by a certified lab (Chelab S.r.l., Merieux NutriSciences Corporation, Resana TV, Italy).…”

“…The compositions of BF and BR-UnF are presented in Table 2 . The compositional analysis of BR-UnF has been reported in a previous publication [ 19 ]. The protein content in BR-UnF (35.80 ± 1.50 g/100 g) was much higher than the protein content quantified in BF (12.96 ± 0.79 g/100 g).…”

“…Ingredients incorporated into bread recipes included bakers’ flour (BF) (Odlums Group, Dublin, Ireland); spent barley rootlets (UnF-BR) supplied by Anheuser-Busch InBev (Leuven, Belgium); a sterilised, freeze-dried BR ingredient (BR-Ster); and five fermented, freeze-dried BR ingredients [ 19 ]. The fermented, freeze-dried BR ingredients were produced using LAB fermentation with the strains listed in Table 1 , as described by Neylon et al [ 19 ].…”

“…Ingredients incorporated into bread recipes included bakers’ flour (BF) (Odlums Group, Dublin, Ireland); spent barley rootlets (UnF-BR) supplied by Anheuser-Busch InBev (Leuven, Belgium); a sterilised, freeze-dried BR ingredient (BR-Ster); and five fermented, freeze-dried BR ingredients [ 19 ]. The fermented, freeze-dried BR ingredients were produced using LAB fermentation with the strains listed in Table 1 , as described by Neylon et al [ 19 ]. Briefly, 12.5% ( w/v ) of BR-UnF were added to water to a final volume of 800 mL and transferred to a 1 L batch bioreactor on a DASGIP Bioblock equipped with DASGIP TC4SC4 and DASGIP PH8 modules (Eppendorf, Stevenage, UK).…”

“…Neylon et al [ 19 ] performed an in-depth analysis of the effect of heat treatment and LAB fermentation (using Weissella cibaria MG1, Lactiplantibacillus plantarum FST1.7, Limosilactobacillus reuteri R29, Leuconostoc citreum TR116, and Lactobacillus amylovorus FST2.11) on BR. Following this, the current study aimed to investigate the effects of the inclusion of fermented BR ingredients in a bread matrix.…”