Fermentation of Agri-Food Waste: A Promising Route for the Production of Aroma Compounds

Dynamic transformation in flavor during hawthorn wine fermentation: Sensory properties and profiles of nonvolatile and volatile aroma compounds coupled with multivariate analysis

Fermentation stage is a crucial factor for flavor profiles formation of hawthon wine. Thus, comprehensive knowledge of dynamic relationship between nonvolatile (NVOCs) and volatile aroma compounds (VOCs) from hawthorn wine at different fermentation stages was investigated by GC-MS and HPLC coupled with multivariate analysis. The increase of alcohols/esters/acids but decrease of terpenes/aldehydes/ketones was observed as fermentation extension. Specifically, OAV of ethyl acetate, ethyl caprylate, and ethyl caprate was > 50 from the 3rd day to 10th day, giving more fruity properties. Multivariate analysis showed that 1-hexanol, ethyl myristate, isobutyric acid, et al., were linked to the sensory evaluation of "sweet", "floral" and "fruity", and fructose, glucose and bitter amino acids were responsible for reduction of "bitterness" and "astringency". Additionally, VOCs were positively correlated with organic acids while negative to amino acids/soluble sugars, probably due to metabolization as precursors, providing references for aroma enhancement by regulating NVOCs precursors.

Transcriptomic analysis reveals differential gene expression patterns of Lacticaseibacillus casei ATCC 393 in response to ultrasound stress

In recent years, there has been a growing interest in modulating the performance of probiotic, mainly Lactic Acid Bacteria (LAB), in the field of probiotic food. Attenuation, induced by sub-lethal stresses, delays the probiotic metabolism, and induces a metabolic shift as survival strategy. In this paper, RNA sequencing was used to uncover the transcriptional regulation in Lacticaseibacillus casei ATCC 393 after ultrasound-induced attenuation. Six (T) and 8 (ST) min of sonication induced a significant differential expression of 742 and 409 genes, respectively. We identified 198 up-regulated and 321 down-regulated genes in T, and similarly 321 up-regulated and 249 down-regulated in ST. These results revealed a strong defensive response at 6 min, followed by adaptation at 8 min. Ultrasound attenuation modified the expression of genes related to a series of crucial biomolecular processes including membrane transport, carbohydrate and purine metabolism, phage-related genes, and translation. Specifically, genes encoding PTS transporters and genes involved in the glycolytic pathway and pyruvate metabolism were up-regulated, indicating an increased need for energy supply, as also suggested by an increase in the transcription of purine biosynthetic genes. Instead, protein translation, a high-energy process, was inhibited with the down-regulation of ribosomal protein biosynthetic genes. Moreover, phage-related genes were down-regulated suggesting a tight transcriptional control on DNA structure. The observed phenomena highlight the cell need of ATP to cope with the multiple ultrasound stresses and the activation of processes to stabilize and preserve the DNA structure. Our work demonstrates that ultrasound has remarkable effects on the tested strain and elucidates the involvement of different pathways in its defensive stress-response and in the modification of its phenotype.

Nutritional upgrade of olive mill stone waste, walnut shell and their mixtures by applying solid state fermentation initiated by Pleurotus ostreatus

Present study concerns the transformation of the agro-industrial by-products olive mill stone waste (OMSW) and walnut shell (WS) to a protein-enriched animal feedstuff utilizing the solid state fermentation (SSF) technique. For this purpose, various mixtures of these by-products were exploited as substrates of the SSF process which was initiated by the P. ostreatus fungus. The respective results indicated that the substrate consisted of 80% WS and 20% OMSW afforded the product with the highest increase in protein content, which accounted the 7.57% of its mass (69.35% increase). In addition, a 26.13% reduction of lignin content was observed, while the most profound effect was observed for their 1,3-1,6 β-glucans profile, which was increased by 3-folds reaching the 6.94% of substrate's mass. These results are indicative of the OMSW and WS mixtures potential to act as efficient substrate for the development of novel proteinaceous animal feed supplements using the SSF procedure. Study herein contributes to the reintegration of the agro-industrial by-products aiming to confront the problem of proteinaceous animal feed scarcity and reduce in parallel the environmental footprint of the agro-industrial processes within the context of circular economy.

Biotransformation of monoterpenes using Streptomyces strains from the rhizosphere of Inga edulis Martius from in an Amazonian urban forest fragment

To investigate the biocatalytic potential of Amazonian actinomycetes for monoterpenes biotransformation. To carry out the present study, eleven actinomycetes of the genus Streptomyces isolated from inga-cipó (Inga edulis Mart.) rhizospheres were tested for their ability to bioconvert the substrates R-(+)-limonene, S-(-)-limonene, 1S-(-)-α-pinene, and (-)-β-pinene as sole carbon and energy source. According to gas chromatography-mass spectrometry analysis, three strains, LabMicra B270, LaBMicrA B310, and LaBMicrA B314, were able to biotransform 1S-(-)-α-pinene after 96 h of growth. However, Streptomyces LaBMicrA B270 was the most promising since it converted after only 72 h all the 1S-(-)-α-pinene mainly into cis-verbenol (74.9±1.24%) and verbenone (18.2±1.20%), compounds that have important biological activities and great industrial interest as additives in foods and cosmetics. These findings can stimulate the development of natural aromas using naturally abundant monoterpenes, ratify the potential of microorganisms from almost unexplored niches such as the Amazonian rhizosphere, and reinforce the importance of preserving those niches.

Effect of microbial fermentation on functional traits and volatiloma profile of pâté olive cake

In this study, the pâté olive cake (POC), a by-product of the olive oil industry, was subjected to fermentation in a bioreactor using three microbial strains, Lactiplantibacillus plantarum, Wickerhamomyces anomalus and Candida boidinii, previously isolated from fermented table olive brines. Chemical, microbiological and molecular analyses were carried out at the beginning and at the end of fermentation. The lowest pH value (4.09) was reached after 10 days in sample inoculated with C. boidinii. Microbiological analyses exhibited the dominance of yeasts throughout the whole process (from 5.5 to 7.80 Log10 CFU/g), as confirmed by PCR-DGGE analysis. The microbial cultures affected both phenolic and volatile organic compound profiles. Moreover, the POC samples treated with different microbial strains were investigated for biological assays. The sample fermented with W. anomalus showed the greatest diffusion speed of transepithelial transport through Caco-2 cell, the highest inhibitory activity towards the tested cyclooxygenases and the highest antioxidant activity.

Microbial Diversity in African Foods and Beverages: A Systematic Assessment

This article provides a comprehensive and in-depth examination of the microbial diversity inherent in African food and beverages, with a particular emphasis on fermented products. It identifies and characterizes the dominant microorganisms, including both prokaryotes and yeasts, prevalent in these foods, and furthermore, critically analyzes the health benefits of these microbial strains, especially their probiotic properties, which could potentially improve digestion and contribute to human health. Notably, it underscores the vital role these microorganisms play in bolstering food security across Africa by enhancing and preserving food quality and safety. It also delves into the potential applications of microbial products, such as metabolites, in the food industry, suggesting their possible use in food processing and preservation. Conclusively, with a summarization of the key findings, emphasizing the importance of gaining a deep understanding of microbial diversity in African beverages and foods. Such knowledge is crucial not only in promoting food security but also in advancing public health.

Lacticaseibacillus Strains Isolated from Raw Milk: Screening Strategy for Their Qualification as Adjunct Culture in Cheesemaking

The microbial ecology fundamentals of raw milk and long-ripened cheeses consist of a complex interaction between starter lactic acid bacteria (SLAB) and non-starter LAB (NSLAB). Although NSLAB aromatic properties are paramount, other phenotypic traits need to be considered for their use as adjunct cultures, such as the capability to endure technological parameters encountered during cheesemaking. The present study focused on the isolation and characterization of NSLAB from spontaneously fermented raw cow's milk coming from 20 dairies that produce Grana Padano PDO cheese. From 122 isolates, the screening process selected the 10 most diverse strains belonging to Lacticaseibacillus spp. to be phenotypically characterized. The strains were tested for their growth performance in milk in combination with the application of technological stresses, for their ability to produce volatile compounds after their growth in milk, and for their ability to use different nutrient sources and resist chemicals. The complex characterization qualified the strains 5959_Lbparacasei and 5296_Lbparacasei as the best candidates to be used as adjunct strains in the production of raw milk and long-ripened cheeses, provided that antibiotic resistance is measured before their employment. Other strains with interesting aromatic capabilities but lower heat resistance were 5293_Lbparacasei, 5649_Lbparacasei and 5780_Lbparacasei, which could be candidates as adjunct strains for uncooked cheese production.

Solid-state fermentation of cassava (Manihot esculenta Crantz): a review

Solid-state fermentation (SSF) is a promising technology for producing value-added products from cassava (Manihot esculenta Crantz). In this process, microorganisms are grown on cassava biomass without the presence of free-flowing liquid. Compared to other processing methods, SSF has several advantages, such as lower costs, reduced water usage, and higher product yields. By enhancing the content of bioactive compounds like antioxidants and phenolic compounds, SSF can also improve the nutritional value of cassava-based products. Various products, including enzymes, organic acids, and biofuels, have been produced using SSF of cassava. Additionally, SSF can help minimize waste generated during cassava processing by utilizing cassava waste as a substrate, which can reduce environmental pollution. The process has also been explored for the production of feed and food products such as tempeh and cassava flour. However, optimizing the process conditions, selecting suitable microbial strains, and developing cost-effective production processes are essential for the successful commercialization of SSF of cassava.

Upcycling in the context of biotechnology-based solutions for food quality, loss, and consumer perception

Wasted food is the single biggest contributor to greenhouse gases. Globally, attempts are being made to both reduce surplus food and divert it into food-to-food operations. This opinion piece covers upcycling and biotechnology-mediated solutions on a technology continuum as a part of the bigger whole to solve this problem. Upcycling is an approach to divert foods that would otherwise be wasted into higher uses that would also have tangible benefits to the environment and society. Likewise, biotechnology can help farmers produce crops with longer shelf life and that satisfy cosmetic standards. Uncertainty, either in the form of food safety, technology, or neophobia in the case of upcycled foods or genes (cisgenic or transgenic) in the case of biotechnology, is a hurdle. Communication and consumer perception should be researched. Both upcycling and biotechnology can provide practical solutions, but their acceptance depends on communication strategies and consumer perception.

Antioxidant and Antiaging Activity of Fermented Coix Seed Polysaccharides on Caenorhabditis elegans

Aging is closely related to many diseases and is a long-term challenge that humans face. The oxidative damage caused by the imbalance of free radicals is an important factor in aging. In this study, we investigate the antioxidant and antiaging activities of fermented coix seed polysaccharides (FCSPs) via in vitro and in vivo experiments. The FCSPs were extracted by fermenting coix seed with Saccharomyces cerevisiae for 48 h and utilizing water-extracted coix seed polysaccharides (WCSPs) as a control. Their antiaging activity and mechanism were evaluated based on the antiaging model organism Caenorhabditis elegans (C. elegans). The results showed that the molecular weight of the FCSPs extracted by fermentation was smaller than that of the WCSPs, making them more easily absorbed and utilized. At a concentration of 5 g/L, the FCSPs' capacity to scavenge the DPPH·, ABTS⁺·, OH·, and O₂^-· radicals was greater than the WCSPs' capacity by 10.09%, 14.40%, 49.93%, and 12.86%, respectively. Moreover, C. elegans treated with FCSPs exhibited higher antioxidant enzyme activities and a lower accumulation of malonaldehyde. By inhibiting the expression of the pro-aging genes daf-2 and age-1, and upregulating the expression of the antiaging genes daf-16, sod-3, skn-1, and gcs-1 in the insulin/insulin-like growth factor-1 (IIS) signaling pathway, the FCSPs could effectively enhance stress tolerance and delay C. elegans aging. The lifespan of C. elegans in the FCSPs group was 5.91% higher than that of the WCSPs group. In conclusion, FCSPs exert better antioxidant and antiaging effects than WCSPs, which can act as a potential functional ingredient or supplement in food.

Delving into Agri-Food Waste Composition for Antibacterial Phytochemicals

The overuse of antibiotics in the healthcare, veterinary, and agricultural industries has led to the development of antimicrobial resistance (AMR), resulting in significant economic losses worldwide and a growing healthcare problem that urgently needs to be solved. Plants produce a variety of secondary metabolites, making them an area of interest in the search for new phytochemicals to cope with AMR. A great part of agri-food waste is of plant origin, constituting a promising source of valuable compounds with different bioactivities, including those against antimicrobial resistance. Many types of phytochemicals, such as carotenoids, tocopherols, glucosinolates, and phenolic compounds, are widely present in plant by-products, such as citrus peels, tomato waste, and wine pomace. Unveiling these and other bioactive compounds is therefore very relevant and could be an important and sustainable form of agri-food waste valorisation, adding profit for local economies and mitigating the negative impact of these wastes' decomposition on the environment. This review will focus on the potential of agri-food waste from a plant origin as a source of phytochemicals with antibacterial activity for global health benefits against AMR.

Value Addition Employing Waste Bio-Materials in Environmental Remedies and Food Sector

Overall, combating food waste necessitates a multifaceted approach that includes education, infrastructure, and policy change. By working together to implement these strategies, we can help reduce the negative impacts of food waste and create a more sustainable and equitable food system. The sustained supply of nutrient-rich agrifood commodities is seriously threatened by inefficiencies caused by agricultural losses, which must be addressed. As per the statistical data given by the Food and Agriculture Organisation (FAO) of the United Nations, nearly 33.33% of the food that is produced for utilization is wasted and frittered away on a global level, which can be estimated as a loss of 1.3 billion metric tons per annum, which includes 30% cereals, 20% dairy products 35% seafood and fish, 45% fruits and vegetables, and 20% of meat. This review summarizes the various types of waste originating from various segments of the food industry, such as fruits and vegetables, dairy, marine, and brewery, also focusing on their potential for developing commercially available value-added products such as bioplastics, bio-fertilizers, food additives, antioxidants, antibiotics, biochar, organic acids, and enzymes. The paramount highlights include food waste valorization, which is a sustainable yet profitable alternative to waste management, and harnessing Machine Learning and Artificial Intelligence technology to minimize food waste. Detail of sustainability and feasibility of food waste-derived metabolic chemical compounds, along with the market outlook and recycling of food wastes, have been elucidated in this review.

A Review on the Challenges and Choices for Food Waste Valorization: Environmental and Economic Impacts

Valorization of food waste (FW) is instrumental for reducing the environmental and economic burden of FW and transitioning to a circular economy. The FW valorization process has widely been studied to produce various end-use products and summarize them; however, their economic, environmental, and social aspects are limited. This study synthesizes some of the valorization methods used for FW management and produces value-added products for various applications, and also discusses the technological advances and their environmental, economic, and social aspects. Globally, 1.3 billion tonnes of edible food is lost or wasted each year, during which about 3.3 billion tonnes of greenhouse gas is emitted. The environmental (-347 to 2969 kg CO₂ equiv/tonne FW) and economic (-100 to $138/tonne FW) impacts of FW depend on the multiple parameters of food chains and waste management systems. Although enormous efforts are underway to reduce FW as well as valorize unavoidable FW to reduce environmental and economic loss, it seems the transdisciplinary approach/initiative would be essential to minimize FW as well as abate the environmental impacts of FW. A joint effort from stakeholders is the key to reducing FW and the efficient and effective valorization of FW to improve its sustainability. However, any initiative in reducing food waste should consider a broader sustainability check to avoid risks to investment and the environment.

Potential and Restrictions of Food-Waste Valorization through Fermentation Processes

Food losses (FL) and waste (FW) occur throughout the food supply chain. These residues are disposed of on landfills producing environmental issues due to pollutants released into the air, water, and soil. Several research efforts have focused on upgrading FL and FW in a portfolio of added-value products and energy vectors. Among the most relevant research advances, biotechnological upgrading of these residues via fermentation has been demonstrated to be a potential valorization alternative. Despite the multiple investigations performed on the conversion of FL and FW, a lack of comprehensive and systematic literature reviews evaluating the potential of fermentative processes to upgrade different food residues has been identified. Therefore, this article reviews the use of FL and FW in fermentative processes considering the composition, operating conditions, platforms, fermentation product application, and restrictions. This review provides the framework of food residue fermentation based on reported applications, experimental, and theoretical data. Moreover, this review provides future research ideas based on the analyzed information. Thus, potential applications and restrictions of the FL and FW used for fermentative processes are highlighted. In the end, food residues fermentation must be considered a mandatory step toward waste minimization, a circular economy, and the development of more sustainable production and consumption patterns.

Olive Mill Wastewater Fermented with Microbial Pools as a New Potential Functional Beverage

Olive mill wastewater (OMWW) represents a by-product but also a source of biologically active compounds, and their recycling is a relevant strategy to recover income and to reduce environmental impact. The objective of the present study was to obtain a new functional beverage with a health-promoting effect starting from OMWW. Fresh OMWW were pre-treated through filtration and/or microfiltration and subjected to fermentation using strains belonging to Lactiplantibacillus plantarum, Candida boidinii and Wickerhamomyces anomalus. During fermentation, phenolic content and hydroxytyrosol were monitored. Moreover, the biological assay of microfiltered fermented OMWW was detected versus tumor cell lines and as anti-inflammatory activity. The results showed that in microfiltered OMWW, fermentation was successfully conducted, with the lowest pH values reached after 21 days. In addition, in all fermented samples, an increase in phenol and organic acid contents was detected. Particularly, in samples fermented with L. plantarum and C. boidinii in single and combined cultures, the concentration of hydroxytyrosol reached values of 925.6, 902.5 and 903.5 mg/L, respectively. Moreover, biological assays highlighted that fermentation determines an increase in the antioxidant and anti-inflammatory activity of OMWW. Lastly, an increment in the active permeability on Caco-2 cell line was also revealed. In conclusion, results of the present study confirmed that the process applied here represents an effective strategy to achieve a new functional beverage.

Enhancing bioflavor production by solid-state fermentation using Kluyveromyces marxianus and l-phenylalanine

This study includes the utilization of sweet lemon peel (SLP) and sugarcane bagasse (SB) in solid-state fermentation using Kluyveromyces marxianus for bioflavor compounds production adopting response surface methodology. The major flavor compounds, 2-phenylethanol (2-PE) and 2-phenylethyl acetate (2-PEA) were quantified using gas chromatography-mass spectrometry with and without adding any supplements. Quantification of flavor compounds indicated that without adding any accessory in the substrate, the concentration of 2-PE using SLP and SB was 0.15 ± 0.003 mg/g and 0.14 ± 0.002 mg/g, respectively. Whereas 2-PEA concentration using SLP and SB was observed as 0.01 ± 0.008 mg/g and 0.02 ± 0.001 mg/g, respectively. The addition of l-phenylalanine (l-phe) in the substrates showed 30%-75% enhancement in the production of 2-PE and 2-PEA. The present study indicates that the K. marxianus is a potential microbial cell factory for the production of 2-PE and 2-PEA with the addition of synthetic l-phe having a plethora of applications in food and pharmaceutical industries.

Current Challenges in the Sustainable Valorisation of Agri-Food Wastes: A Review

In the upcoming years, the world will face societal challenges arising, in particular, from the impact of climate change and the inefficient use of natural resources, in addition to an exponential growth of the world population, which according to the United Nations (UN) estimations will be 9.8 billion in 2050. This increasing trend requires optimized management of natural resources with the use of value-added waste and a significant reduction in food loss and food waste. Moreover, the recent pandemic situation, COVID-19, has contributed indisputably. Along with the agri-food supply chain, several amounts of waste or by-products are generated. In most cases, these biomass wastes cause serious environmental concerns and high costs to enterprises. The valorisation of the agri-food loss and food industry wastes emerged as a useful strategy to produce certain value-added compounds with several potential applications, namely in the food, health, pharmaceutical, cosmetic, and environmental fields. Therefore, in this review, some of the crucial sustainable challenges with impacts on the valorisation of agri-food loss/wastes and by-products are discussed and identified, in addition to several opportunities, trends and innovations. Potential applications and usages of the most important compounds found in food loss/waste will be highlighted, with a focus on the food industry, pharmaceutical industry, and the environment.

Bread Surplus: A Cumulative Waste or a Staple Material for High-Value Products?

Food waste has been widely valorized in the past years in order to develop eco-friendly materials. Among others, bread waste is currently of increasing interest, as it is considered a huge global issue with serious environmental impacts and significant economic losses that have become even greater in the post-pandemic years due to an increase in cereal prices, which has led to higher production costs and bread prices. Owing to its richness in polysaccharides, bread waste has been previously studied for its physico-chemical characteristics and its numerous biotechnological applications. The present review highlights the re-use of bread waste and its valorization as a valuable resource by making value-added products through numerous technological processes to increase efficiency at all stages. Many research studies reporting several transformation methods of surplus bread into ethanol, lactic acid, succinic acid, biohydrogen, hydroxymethylfurfural, proteins and pigments, glucose-fructose syrup, aroma compounds, and enzymes are widely discussed. The wide variety of suggested applications for recycling bread waste provides significant insights into the role of technology development in potentially maximizing resource recovery and consequently contributing to environmental performance by reducing the amount of bread waste in landfills.

Reintegration of Food Industry By-Products: Potential Applications

Numerous studies have indicated that fruits and vegetables are considered as significant sources of bioactive compounds. The generated by-products, which are derived from the food industry, reveal similar or higher antioxidant activity. On the other hand, intense industrialization results in the production of large volumes of by-products, raising serious environmental issues. Therefore, this situation creates the necessity to develop new strategies in order to exploit the generated wastes, securing the ability to develop new high-added-value products. This review aims to summarize the exploitation of fruit wastes, namely, apple and citrus, as well as vegetable by-products which are derived from tomato, potato and carrot cultivation. All the aforementioned by-products have found wide applications in the development of new high-added-value products in the food and feed industry owing to their improved nutritional profiles. Furthermore, these wastes are characterized by a strong antioxidant activity, justifying their valorization in other fields such as cosmetics and pharmaceutical industries.

Emerging challenges for the agro-industrial food waste utilization: A review on food waste biorefinery

Modernization and industrialization has undoubtedly revolutionized the food and agro-industrial sector leading to the drastic increase in their productivity and marketing thereby accelerating the amount of agro-industrial food waste generated. In the past few decades the potential of these agro-industrial food waste to serve as bio refineries for the extraction of commercially viable products like organic acids, biochemical and biofuels was largely discussed and explored over the conventional method of disposing in landfills. The sustainable development of such strategies largely depends on understanding the techno economic challenges and planning for future strategies to overcome these hurdles. This review work presents a comprehensive outlook on the complex nature of agro-industrial food waste and pretreatment methods for their valorization into commercially viable products along with the challenges in the commercialization of food waste bio refineries that need critical attention to popularize the concept of circular bio economy.

Novel Approaches in the Valorization of Agricultural Wastes and Their Applications

Worldwide, a huge amount of agricultural food wastes and byproducts containing valuable bioactive compounds are generated, especially throughout the entire supply chain. Minimizing food wastes and byproducts is the first option to avoid environmental problems, and to help the economy and the society. Although many countries implement policies to reduce food wastes and byproducts, and different management methods are available to utilize agricultural food wastes, they are still produced annually. Nanotechnological and biotechnological approaches are recently used as novel and green applications to valorize agricultural food wastes and improve their stability and applicability. In this Review, these approaches are covered in detail with given examples. Another valorization way of consumable food waste is using it for functional food production. This Review focuses on specific examples of functional foods with food waste as an ingredient. In addition, the problems and limitations of waste management and valorization methods are investigated, considering future perspectives.

The anti-aging activity of Lycium barbarum polysaccharide extracted by yeast fermentation: In vivo and in vitro studies

Lycium barbarum polysaccharide (LBP) is an important active substance in Lycium barbarum. In this study, LBP was extracted by the hot water method and yeast fermentation method to obtain products called LBP-W and LBP-Y, respectively. Both LBPs have a strong ability to scavenge DPPH, hydroxyl, and superoxide anion free radicals and have a total antioxidant capacity. Both LBPs prolong the lifespan of C. elegans under normal conditions, oxidative stress and heat stress and do not affect fertility, LBPs could prolong the lifespan of C. elegans by upregulating the expression of daf-16, sod-3 and hsp-16.2 genes, and LBP-Y is more efficacious. The molecular weight of the LBPs was characterized by gel permeation chromatography (GPC), and the results showed that LBP-Y is smaller and more uniform than LBP-W. The skin penetration experiment showed that the absorption effect of LBP-Y is better than that of LBP-W. These lines of evidence suggest that the yeast fermentation extraction of LBP produces better antioxidant and anti-aging effects than those obtained with the traditional hot water extraction, which is more suitable for obtaining raw materials with anti-aging functions that can potentially be used in the food and cosmetic industries.

Exploring the Potential of Lactic Acid Fermentation for the Recovery of Exhausted Vanilla Beans

The market value of vanilla is constantly growing, as it is the aroma most appreciated by consumers worldwide. The key component of the aroma of vanilla beans is vanillin, which can be directly extracted from the plant, produced by chemical synthesis, or by bioconversion of natural precursors. Due to the increasing consumers' demand for products labeled as "natural," extraction from vanilla pods results in a more valuable aroma source. Once the extraction is completed, what remains are the exhausted beans that still contain small seeds and other compounds, including varying amounts of vanillin trapped in the cellular structures of the plant. The application of fermentation of exhausted vanilla beans is proposed here as a strategy to recover "natural" vanillin and other valuable aroma compounds as a result of the metabolic conversion by lactic acid bacteria (LAB). The aim of this study was to verify the fermentability of exhausted vanilla beans by-products for their valorization, allowing the recovery of high-value molecules or new applications in food products. Design of Experiment (DoE) was used to screen a library of LAB strains to identify the best condition of fermentation in response to varying cultivation conditions. A comparison between mono and co-culture of LAB was assessed. Moreover, sensory panel tests and the evaluation of the aromatic components by Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry analysis were carried out to better understand the modification of the aroma profile after fermentation. Fermentation with LAB changed the volatile profile and sensory characteristics of the exhausted vanilla beans and represents a promising method for the valorization of these by-products.

Production of lactones for flavoring and pharmacological purposes from unsaturated lipids: an industrial perspective

The enantiomeric pure and natural (+)-Lactones (C ≤ 14) with aromas obtained from fruits and milk are considered flavoring compounds. The flavoring value is related to the lactones' ring size and chain length, which blend in varying concentrations to produce different stone-fruit flavors. The nature-identical and enantiomeric pure (+)-lactones are only produced through whole-cell biotransformation of yeast. The industrially important γ-decalactone and δ-decalactone are produced by a four-step aerobic-oxidation of ricinoleic acid (RA) following the lactonization mechanism. Recently, metabolic engineering strategies have opened up new possibilities for increasing productivity. Another strategy for increasing yield is to immobilize the RA and remove lactones from the broth regularly. Besides flavor impact, γ-, δ-, ε-, ω-lactones of the carbon chain (C8-C12), the macro-lactones and their derivatives are vital in pharmaceuticals and healthcare. These analogues are isolated from natural sources or commercially produced via biotransformation and chemical synthesis processes for medicinal use or as active pharmaceutical ingredients. The various approaches to biotransformation have been discussed in this review to generate more prospects from a commercial point of view. Finally, this work will be regarded as a magical brick capable of containing both traditional and genetic engineering technology while contributing to a wide range of commercial applications.

Improved Foods Using Enzymes from Basidiomycetes

Within the kingdom of fungi, the division Basidiomycota represents more than 30,000 species, some with huge genomes indicating great metabolic potential. The fruiting bodies of many basidiomycetes are appreciated as food (“mushrooms”). Solid-state and submerged cultivation processes have been established for many species. Specifically, xylophilic fungi secrete numerous enzymes but also form smaller metabolites along unique pathways; both groups of compounds may be of interest to the food processing industry. To stimulate further research and not aim at comprehensiveness in the broad field, this review describes some recent progress in fermentation processes and the knowledge of fungal genetics. Processes with potential for food applications based on lipases, esterases, glycosidases, peptidases and oxidoreductases are presented. The formation and degradation of colourants, the degradation of harmful food components, the formation of food ingredients and particularly of volatile and non-volatile flavours serve as examples. In summary, edible basidiomycetes are foods—and catalysts—for food applications and rich donors of genes to construct heterologous cell factories for fermentation processes. Options arise to support the worldwide trend toward greener, more eco-friendly and sustainable processes.

Microbial Degradation and Value Addition to Food and Agriculture Waste

Food and agriculture waste (FAW) is a serious problem that is increasing globally. Wastage of raw materials or processed food due to various man-made activities is huge. This solid waste which is either being discarded by humans in their daily activities or an obligatory residue of agricultural processes is severely harming our environment. This becomes a major concern in densely populated agri-based countries, like India, China, and the USA. It is strongly debated that such issues need to be addressed very emphatically for sustainable development of ourselves and our surroundings. Lots of economic benefits can be obtained by reducing the food loss or converting the agricultural waste into useful products and these advantages can be in the form of better food security, reduced production cost, biodegradable products, and environment sustainability with cleaner options to reduce the ever-increasing global problem of garbage and waste management. Proper management of these substances can considerably lessen the risks to individual health. Reprocessing of waste is of great advantage as FAW has many components which may form an available resource to be converted to another useful product. Several approaches have been made for converting food waste into fruitful products. Bioconversion being the most prominent approach is helping us in a major way to overcome the problem of FAW. Microorganisms are at the forefront of this and have been extensively explored for their bioconversion potential. The present work focuses on the current state of food and agriculture waste and their valorization approaches. Through extensive literature review, we have highlighted and discussed the potential of microorganisms in bioconversion of waste, major types of functional ingredients derived during the process, and potential constraints in implementation of such state-of-the-art technology at industrial scale. The review also gives a brief technical overview of the conversion of waste products into energy generation and biofuels.

Olive Mill by-Products Thermochemical Conversion via Hydrothermal Carbonization and Slow Pyrolysis: Detailed Comparison between the Generated Hydrochars and Biochars Characteristics

In this research work, an ecofriendly approach was adopted for the treatment of two abundant liquid and solid agricultural wastes generated by olive mill industry: olive mill wastewater (OMWW) and raw olive pomace (ROP). It consists, firstly of the impregnation of ROP by OMWW and the conversion of the resulting impregnated sample (IROP) into hydrochars and biochars through hydrothermal carbonization (HTC) and slow pyrolysis methods, respectively. The impact of the treatment temperature on the physico-chemical properties of the derived chars was assessed by various analytical techniques. The hydrochars production yields were found to be higher than the biochars ones and associated to the lower temperature used. However, the generated biochars possess higher carbon percentage and lower volatile matter contents. In addition, the increase of the hydrothermal and pyrolysis carbonization temperatures shows an increase of macro-elements contents and a significant decrease of the O/C ratios which led to an enhancement of the high heating value for both hydrochars and biochars. The FTIR and Boehm titration analysis highlighted a significant alteration of the biochars surface chemistry compared to hydrochars evidenced by the lower amount of functional groups. The collected data emphasize on the efficient potential application of hydrochars and biochars for agricultural and environmental applications, respectively. Furthermore, it was noted that both chars have high energetic potentials and could be used for co-firing with coal in industrial boilers.

Nonconventional yeasts to produce aroma compounds by using agri-food waste materials

Nowadays, biotechnological applications are emphasized to ensure sustainable development by reutilizing waste materials to prevent ecological problems and to produce or recover compounds that may have positive effects on health. Yeasts are fascinating microorganisms that play a key role in several traditional and innovative processes. Although Saccharomyces is the most important genus of yeasts, and they are major producers of biotechnological products worldwide, a variety of other yeast genera and species than Saccharomyces that are called 'non-Saccharomyces' or 'nonconventional' yeasts also have important potential for use in biotechnological applications. Some of the nonconventional yeast strains offer a unique potential for biotechnological applications to produce valuable secondary metabolites due to their characteristics of surviving and growing in such extreme conditions, e.g. wide substrate range, rapid growth, thermotolerance, etc. In this review, we aimed to summarize potential biotechnological applications of some nonconventional yeasts (Kluyveromyces spp., Yarrowia spp., Pichia spp., Candida spp., etc.) to produce industrially important aroma compounds (phenylethyl alcohol, phenylethyl acetate, isobutyl acetate, diacetyl, etc.) by reutilizing agri-food waste materials in order to prevent ecological problems and to produce or recover compounds that may have positive effects on health.

Selection of Autochthonous LAB Strains of Unripe Green Tomato towards the Production of Highly Nutritious Lacto-Fermented Ingredients

Lactic fermentation of unripe green tomatoes as a tool to produce food ingredients is a viable alternative for adding value to industrial tomatoes unsuitable for processing and left in large quantities in the fields. Fermentation using starter cultures isolated from the fruit (plant-matrix adapted) can have advantages over allochthonous strains in obtaining fermented products with sensory acceptability and potentially probiotic characteristics. This paper details the characterisation of the unripe green tomato lactic microbiota to screen LAB strains for use as starter cultures in fermentation processes, along with LAB strains available from INIAV's collection. Morphological, biochemical (API system), and genomic (16S rDNA gene sequencing) identification showed that the dominant LAB genera in unripe green tomato are Lactiplantibacillus, Leuconostoc, and Weissella. Among nine tested strains, autochthonous Lactiplantibacillus plantarum and allochthonous Weissella paramesenteroides showed tolerance to added solanine (200 ppm) and the best in vitro probiotic potential. The results indicate that the two LAB strains are promising candidates for manufacturing probiotic fermented foods from unripe green tomatoes.

Food Waste on Foodservice: An Overview through the Perspective of Sustainable Dimensions

Food waste (FW) is a current, complex, and widely debated issue in various spheres of society. Globally, about 2.6 trillion dollars per year is lost because of wasted food. Part of FW is preventable, and it is necessary to identify where it occurs. In most cases, FW occurs at the end of the production chain (meal preparation and distribution). Identifying the main food service failures on FW is important for developing efficient strategies for reducing them. Therefore, this study aimed to perform a narrative review of the impacts caused by FW in food services considering the three dimensions of sustainability (social, economic, or environmental). Multiple reasons were identified in this review that impacts those three dimensions, such as the cost of wasted raw material, use of cleaning material, the energy consumption, salary of food handlers, the water footprint, the amounts of rest-intake, production waste, energy density wasted, use of organic food, and food donation. Identifying these aspects can contribute to reduce FW impacts for better sustainable development, develop tools to measure FW, and assist food service managers in minimizing FW.

Antimicrobial Activity of Fermented Vegetable Byproduct Extracts for Food Applications

To prevent foodborne diseases and extend shelf-life, antimicrobial agents may be used in food to inhibit the growth of undesired microorganisms. In addition to the prevention of foodborne diseases, another huge concern of our time is the recovery of agri-food byproducts. In compliance with these challenges, the aim of this work was to more deeply investigate the antimicrobial activity of extracts derived from fermented tomato, melon, and carrot byproducts, previously studied. All the fermented extracts had antimicrobial activity both in vitro and in foodstuff, showing even higher activity than commercial preservatives, tested for comparison against spoilage microorganisms and foodborne pathogens such as Salmonella spp., L. monocytogenes, and B. cereus. These promising results highlight an unstudied aspect for the production of innovative natural preservatives, exploitable to improve the safety and shelf-life of various categories of foodstuff.