Exploitation of Food Industry Waste for High-Value Products

Bioenergy Potential from Food Waste in California

Food waste makes up approximately 15% of municipal solid waste generated in the United States, and 95% of food waste is ultimately landfilled. Its bioavailable carbon and nutrient content makes it a major contributor to landfill methane emissions, but also presents an important opportunity for energy recovery. This paper presents the first detailed analysis of monthly food waste generation in California at a county level, and its potential contribution to the state's energy production. Scenarios that rely on excess capacity at existing anaerobic digester (AD) and solid biomass combustion facilities, and alternatives that allow for new facility construction, are developed and modeled. Potential monthly electricity generation from the conversion of gross food waste using a combination of AD and combustion varies from 420 to 700 MW, averaging 530 MW. At least 66% of gross high moisture solids and 23% of gross low moisture solids can be treated using existing county infrastructure, and this fraction increases to 99% of high moisture solids and 55% of low moisture solids if waste can be shipped anywhere within the state. Biogas flaring practices at AD facilities can reduce potential energy production by 10 to 40%.

A biorefinery for efficient processing and utilization of spent pulp of Colombian Andes Berry (Rubus glaucus Benth.): Experimental, techno-economic and environmental assessment

This work investigated a model biorefinery for producing phenolic compounds extract, ethanol and xylitol from spent blackberry pulp (SBP). The biorefinery was investigated according to four potential scenarios including mass and heat integrations as well as cogeneration system for supplying part of the energy requirements in the biorefinery. The investigated SBP had 61.54% holocellulose; its total phenolic compounds was equivalent to 2700mg of gallic acid/100g SBP, its anthocyanins content was 126.41mg/kg of SBP and its total antioxidant activity was 174.8μmol TE/g of SBP. The economic analysis revealed that the level of integration in the biorefinery significantly affected the total production cost. The sale-to-total-production-cost ratio indicated that both, mass and heat integrations are of importance relevance. The cost of supplies (enzymes and reagents) had the most significant impact on the total production cost and accounted between 46.72 and 58.95% of the total cost of the biorefinery.

An Investigation into Spent Coffee Waste as a Renewable Source of Bioactive Compounds and Industrially Important Sugars

Conventional coffee brewing techniques generate vast quantities of spent espresso grounds (SEGs) rich in lignocellulose and valuable bioactives. These bioactive compounds can be exploited as a nutraceutical or used in a range of food products, while breakdown of lignocellulose generates metabolizable sugars that can be used for the production of various high-value products such as biofuels, amino acids and enzymes. Response surface methodology (RSM) was used to optimize the enzymatic saccharification of lignocellulose in SEGs following a hydrothermal pretreatment. A maximum reducing sugar yield was obtained at the following optimized hydrolysis conditions: 4.97 g of pretreated SEGs, 120 h reaction time, and 1246 and 250 µL of cellulase and hemicellulase, respectively. Industrially important sugars (glucose, galactose and mannose) were identified as the principal hydrolysis products under the studied conditions. Total flavonoids (p = 0.0002), total polyphenols (p = 0.03) and DPPH free-radical scavenging activity (p = 0.004) increased significantly after processing. A 14-fold increase in caffeine levels was also observed. This study provides insight into SEGs as a promising source of industrially important sugars and polyphenols.

Microbial Enzyme Production Using Lignocellulosic Food Industry Wastes as Feedstock: A Review

Enzymes are of great importance in the industry due to their substrate and product specificity, moderate reaction conditions, minimal by-product formation and high yield. They are important ingredients in several products and production processes. Up to 30% of the total production cost of enzymes is attributed to the raw materials costs. The food industry expels copious amounts of processing waste annually, which is mostly lignocellulosic in nature. Upon proper treatment, lignocellulose can replace conventional carbon sources in media preparations for industrial microbial processes, such as enzyme production. However, wild strains of microorganisms that produce industrially important enzymes show low yield and cannot thrive on artificial substrates. The application of recombinant DNA technology and metabolic engineering has enabled researchers to develop superior strains that can not only withstand harsh environmental conditions within a bioreactor but also ensure timely delivery of optimal results. This article gives an overview of the current complications encountered in enzyme production and how accumulating food processing waste can emerge as an environment-friendly and economically feasible solution for a choice of raw material. It also substantiates the latest techniques that have emerged in enzyme purification and recovery over the past four years.

Antioxidant and Antitumor Activity of a Bioactive Polyphenolic Fraction Isolated from the Brewing Process

There is increasing interest in identifying natural bioactive compounds that can improve mitochondrial functionality and regulate apoptosis. The brewery industry generates wastewater that could yield a natural extract containing bioactive phenolic compounds. Polyphenols act as antioxidants and have been documented to protect the human body from degenerative diseases such as cardiovascular diseases or cancer. The main aims of our research were to determine the phenolic profile of a crude extract obtained (at pilot scale) from a brewery waste stream and to evaluate the biochemical activity of this extract on the mitochondrial function of a cancer cell line (SH-SY5Y). This work is a basic translational pilot study. The total phenolic content was determined by the Folin-Ciocalteu assay, which revealed that 2.30% of the extract consisted of phenolic compounds. The polyphenols, identified and quantified by reverse-phase-high-performance liquid chromatography and mass spectrometry (RP-HPLC/MS), were mainly flavonoids. After cell culture, the tumoral cells treated with the polyphenolic extract showed enhanced mitochondrial oxidative function, which is likely related to a decrease in oxidative stress and an increase in mitochondrial biogenesis. This type of brewery waste stream, properly treated, may be a promising source of natural antioxidants to replace the synthetic antioxidants currently used in the food industry.

Progress towards Sustainable Utilisation and Management of Food Wastes in the Global Economy

In recent years, the problem of food waste has attracted considerable interest from food producers, processors, retailers, and consumers alike. Food waste is considered not only a sustainability problem related to food security, but also an economic problem since it directly impacts the profitability of the whole food supply chain. In developed countries, consumers are one of the main contributors to food waste and ultimately pay for all wastes produced throughout the food supply chain. To secure food and reduce food waste, it is essential to have a comprehensive understanding of the various sources of food wastes throughout the food supply chain. The present review examines various reports currently in the literature and quantifies waste levels and examines the trends in wastage for various food sectors such as fruit and vegetable, fisheries, meat and poultry, grain, milk, and dairy. Factors contributing to food waste, effective cost/benefit food waste utilisation methods, sustainability and environment considerations, and public acceptance are identified as hurdles in preventing large-scale food waste processing. Thus, we highlight the need for further research to identify and report food waste so that government regulators and food supply chain stakeholders can actively develop effective waste utilisation practices.

Modification and Potential Application of Short-Chain-Length Polyhydroxyalkanoate (SCL-PHA)

As the only kind of naturally-occurring biopolyester synthesized by various microorganisms, polyhydroxyalkanoate (PHA) shows a great market potential in packaging, fiber, biomedical, and other fields due to its biodegradablity, biocompatibility, and renewability. However, the inherent defects of scl-PHA with low 3HV or 4HB content, such as high stereoregularity, slow crystallization rate, and particularly the phenomena of formation of large-size spherulites and secondary crystallization, restrict the processing and stability of scl-PHA, as well as the application of its products. Many efforts have focused on the modification of scl-PHA to improve the mechanical properties and the applicability of obtained scl-PHA products. The modification of structure and property together with the potential applications of scl-PHA are covered in this review to give a comprehensive knowledge on the modification and processing of scl-PHA, including the effects of physical blending, chemical structure design, and processing conditions on the crystallization behaviors, thermal stability, and mechanical properties of scl-PHA.

Polyphenol Oxidase Containing Sidestreams as Emulsifiers of Rumen Bypass Linseed Oil Emulsions: Interfacial Characterization and Efficacy of Protection against in Vitro Ruminal Biohydrogenation

The low transfer in ruminants of dietary polyunsaturated fatty acids to the milk or peripheral tissues is largely due to ruminal biohydrogenation. Lipids emulsified by a polyphenol oxidase (PPO) rich protein extract of red clover were shown before to be protected against this breakdown after cross-linking with 4-methylcatechol. Protein extracts of 13 other vegetal resources were tested. Surprisingly, the effectiveness to protect emulsified lipids against in vitro ruminal biohydrogenation largely depended on the origin of the extract and its protein concentration but was not related to PPO activity. Moreover, PPO isoforms in vegetal sources, effectively protecting emulsified lipids, were diverse and their presence at the emulsion interface did not seem essential. Potato tuber peels were identified as an interesting biological source of emulsifying proteins and PPO, particularly since protein extracts of industrial potato sidestreams proved to be suitable for the current application.