Bread waste to lactic acid: Applicability of simultaneous saccharification and solid state fermentation

Harnessing the dual nature of Bacillus (Weizmannia) coagulans for sustainable production of biomaterials and development of functional food

Bacillus coagulans, recently renamed Weizmannia coagulans, is a spore-forming bacterium that has garnered significant interest across various research fields, ranging from health to industrial applications. The probiotic properties of W. coagulans enhance intestinal digestion, by releasing prebiotic molecules including enzymes that facilitate the breakdown of not-digestible carbohydrates. Notably, some enzymes from W. coagulans extend beyond digestive functions, serving as valuable biotechnological tools and contributing to more sustainable and efficient manufacturing processes. Furthermore, the homofermentative thermophilic nature of W. coagulans renders it an exceptional candidate for fermenting foods and lignocellulosic residues into L-(+)-lactic acid. In this review, we provide an overview of the dual nature of W. coagulans, in functional foods and for the development of bio-based materials.

Changes in the Physicochemical Properties of Chia (Salvia hispanica L.) Seeds during Solid-State and Submerged Fermentation and Their Influence on Wheat Bread Quality and Sensory Profile

This study aimed at investigating the impacts of 24 h of either solid-state fermentation (SSF) or submerged fermentation (SMF) with Lactiplantibacillus plantarum strain No. 122 on the physico-chemical attributes of chia seeds (CS). Furthermore, this study examined how adding fermented chia seeds (10, 20, and 30% concentrations) affected the properties and sensory profile of wheat bread. Acidity, lactic acid bacteria (LAB) viable counts, biogenic amine (BA), and fatty acid (FA) profiles of fermented chia seeds were analysed. The main quality parameters, acrylamide concentration, FA and volatile compound (VC) profiles, sensory characteristics, and overall acceptability of the obtained breads, were analysed. A decline in the concentration of certain BA and saturated FA and an increase in polyunsaturated FA and omega-3 (ω-3) were found in fermented CS (FCS). The same tendency in the FA profile was observed in both breads, i.e., breads with non-fermented CS (NFCS) or FCS. The quality parameters, VC profile, and sensory attributes of wheat bread were significantly affected by the addition of NFCS or FCS to the main bread formula. All supplemented breads had reduced specific volume and porosity, but SSF chia seeds increased moisture and decreased mass loss after baking. The lowest acrylamide content was found in bread with a 30% concentration of SSF chia seeds (11.5 µg/kg). The overall acceptance of supplemented breads was lower than the control bread, but breads with 10 and 20% SMF chia seed concentrations were still well accepted (on average, 7.4 score). Obtained results highlight that fermentation with Lp. plantarum positively contributes to chia seed nutritional value, while incorporation of NFCS and FCS at certain levels results in an improved FA profile, certain sensory attributes, and reduced acrylamide content in wheat bread.

Exploring Greek Citizens’ Circular Thinking on Food Waste Recycling in a Circular Economy—A Survey-Based Investigation

Food waste is one of the biggest global challenges. Thinking and acting for closed-loop cycles for energy and resources recovery is pivotal for meeting the Sustainable Development Goal 12.3 (SDG 12.3) by 2030. In this paper, the multifaceted problem of food waste and Greece’s national policy of circular economy is briefly given. Greece produces the highest annual per capita food waste output (142 kg) in Europe, indicating that the problem is rather large for the country. The solution to the problem inextricably linked to the implementation of the food waste hierarchy, was investigated through a survey integrating the possibility of energy recovery. The tailored questionnaire sent via e-mails and social media with the goal of identifying a snapshot of Greek citizens’ conceptions and practices regarding the management of their household food waste, and their familiarity with circular economy concepts. Results have shown that most respondents are aware of the problem’s existence, however, without considering it as important, according to 1565 responses gathered and analyzed using the IBM SPSS Statistics 27.0 program. Greek individuals are eager to recycle their food waste without expecting anything in return, but the majority seek recommendations on how to do it.

Recycling bread waste into chemical building blocks using a circular biorefining approach

Food waste is a global problem, causing significant environmental harm and resulting in substantial economic losses globally. Bread is the commonly wasted food item in the developed world and presents a severe problem for the majority of European nations. It is the second most wasted food item in the UK after potatoes, with an equivalent of 20 million slices of bread thrown away daily. Bread is a starchy material and a rich and clean source of easily extractable fermentable sugars - this is in direct contrast to lignocellulosic feedstocks where harsh physical, chemical and/or enzymatic pretreatment processes are required for release of fermentable sugars. Furthermore, these necessary lignocellulosic pretreatment methods often produce sugars contaminated with fermentation inhibitors. Therefore, bread waste presents a clear opportunity as a potential carbon source for novel commercial processes and, to this end, several alternative routes have been developed to utilize bread waste. Possibilities for direct recycling of bread waste within the food industry are limited due to the relatively short material lifetime, stringent process and hygiene requirements. Anaerobic digestion (AD) and incineration are commonly employed methods for the valorisation of bread waste, generating limited amounts of green energy but with little other environmental or economic benefits. Most food wastes and by-products in the UK including bakery waste are treated through AD processes that fail to harness the full potential of the these wastes. This short communication reviews the challenges of handling bread waste, with a focus on a specific UK scenario. The review will consider how bread waste is generated across the supply chain, current practices to deal with the waste and logistics challenges in waste collection. The presence of clean and high-quality fermentable sugars, proteins and other nutrients in bread make it an ideal substrate for generating chemicals, fuels, bioplastics, pharmaceuticals and other renewable products through microbial fermentations. We suggest potential applications for recycling bread waste into its chemical building blocks through a fermentative route where a circular biorefining approach could maximize resource recovery and environmental savings and eliminate waste to as close to zero as possible.