Mehmet Melikoglu

Analysing global food waste problem: pinpointing the facts and estimating the energy content

Food waste is a global problem. Each year food worth billions of dollars is wasted by the developed economies of the world. When food is wasted, the problem does not end at that point. More than 95% of the food waste ends at landfill sites, where converted into methane, carbon dioxide and other greenhouse gasses by anaerobic digestion. The impact of food waste to climate change is catastrophic. Food waste problem tends to increase in next 25 years due to economic and population growth mainly in Asian countries. In addition, when food wastes buried at landfill sites their energy content is lost. Although food waste is a huge problem, its global size and extent has recently become a hot topic in the academic community. This paper summarises the size of the global food waste problem together with the estimation of the amount of energy lost when food wastes dumped at landfill sites. Calculations in this study also revealed that energy lost at landfill sites equals to 43% of the delivered energy used for the preparation of foods in the US, 37% of the hydroelectric power generation of Japan, and more than 100% of the current annual renewable energy demand of UK industries.

Fermentative Polyhydroxybutyrate Production from a Novel Feedstock Derived from Bakery Waste

In this study, Halomonas boliviensis was cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB) production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized by Halomonas boliviensis while PHB contents between 10 and 30% (w/w) were obtained. Furthermore, three methods for bakery waste hydrolysis were investigated for feedstock preparation. These include: (1) use of crude enzyme extracts from Aspergillus awamori, (2) Aspergillus awamori solid mashes, and (3) commercial glucoamylase. In the first method, the resultant free amino nitrogen (FAN) concentration in hydrolysates was 150 and 250 mg L−1 after 20 hours at enzyme-to-solid ratios of 6.9 and 13.1 U g−1, respectively. In both cases, the final glucose concentration was around 130–150 g L−1. In the second method, the resultant FAN and glucose concentrations were 250 mg L−1 and 150 g L−1, respectively. In the third method, highest glucose and lowest FAN concentrations of 170–200 g L−1 and 100 mg L−1, respectively, were obtained in hydrolysates after only 5 hours. The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

Use of waste bread to produce fermentation products

Abstract: Bread, the staple of the west and, increasingly, the rest of the world, is also one of the most heavily wasted of all food products. Currently, much of this waste is disposed of in landfill sites where it decomposes to methane and carbon dioxide. Yet it is a potentially valuable, renewable resource for the production of chemicals. This chapter explores the opportunities for enhancing the value of this cereal-based waste food through the use of fermentation. Following a review of the literature concerning bread waste utilization, potential process systems are proposed and examined. As bread is a solid raw material, solid state fermentation is preferred as the most efficient means of delivering bioprocesses, and some preliminary optimization studies are presented.

Solid-State Fermentation of Wheat Pieces by Aspergillus oryzae: Effects of Microwave Pretreatment on Enzyme Production in a Biorefinery

Production of hydrolytic enzymes is crucial to operate successful cereal-based biorefineries, where macromolecules in cereals (such as starch, protein, and phosphorus), are converted into their monomers (glucose, free amino nitrogen, and free phosphorous, respectively) for the production of different value-added products. In this study, effects of microwave pretreatment on enzyme production during solid-state fermentations of wheat pieces by Aspergillus oryzae were studied. Results showed that microwave pretreatment for a duration of 30 seconds increased glucoamylase and protease activities from 20 and 143 U/g (db, dry basis), in the control experiment, to 32 and 179 U/g (db), respectively.

Chapter 4 – Use of Waste Bread to Produce Fermentation Products

Abstract: Bread, the staple of the west and, increasingly, the rest of the world, is also one of the most heavily wasted of all food products. Currently, much of this waste is disposed of in landfill sites where it decomposes to methane and carbon dioxide. Yet it is a potentially valuable, renewable resource for the production of chemicals. This chapter explores the opportunities for enhancing the value of this cereal-based waste food through the use of fermentation. Following a review of the literature concerning bread waste utilization, potential process systems are proposed and examined. As bread is a solid raw material, solid state fermentation is preferred as the most efficient means of delivering bioprocesses, and some preliminary optimization studies are presented.

Mathematical modelling of temperature effect on growth kinetics of Pseudomonas spp. on sliced mushroom (Agaricus bisporus)

The growth data of Pseudomonas spp. on sliced mushrooms (Agaricus bisporus) stored between 4 and 28°C were obtained and fitted to three different primary models, known as the modified Gompertz, logistic and Baranyi models. The goodness of fit of these models was compared by considering the mean squared error (MSE) and the coefficient of determination for nonlinear regression (pseudo-R2). The Baranyi model yielded the lowest MSE and highest pseudo-R2 values. Therefore, the Baranyi model was selected as the best primary model. Maximum specific growth rate (rmax) and lag phase duration (λ) obtained from the Baranyi model were fitted to secondary models namely, the Ratkowsky and Arrhenius models. High pseudo-R2 and low MSE values indicated that the Arrhenius model has a high goodness of fit to determine the effect of temperature on rmax. Observed number of Pseudomonas spp. on sliced mushrooms from independent experiments was compared with the predicted number of Pseudomonas spp. with the models used by considering the Bf and Af values. The Bf and Af values were found to be 0.974 and 1.036, respectively. The correlation between the observed and predicted number of Pseudomonas spp. was high. Mushroom spoilage was simulated as a function of temperature with the models used. The models used for Pseudomonas spp. growth can provide a fast and cost-effective alternative to traditional microbiological techniques to determine the effect of storage temperature on product shelf-life. The models can be used to evaluate the growth behaviour of Pseudomonas spp. on sliced mushroom, set limits for the quantitative detection of the microbial spoilage and assess product shelf-life.

Biochemical production of bioalcohols

Bioalcohols can be simply defined as alcohols produced from biological resources or biomass. Bioethanol, which is the major alternative fuel for spark ignition engines, is the most widely known and produced bioalcohol. Bioalcohols can be produced from a wide range of biomass, including crops, lignocellulosic crops or residues, and food waste. The first generation bioalcohols are produced from crops, which sometime creates food versus fuel debate and other issues. The second generation bioalcohols are produced from lignocellulosic biomass, such as forestry or agricultural residues. While the first generation bioalcohols is successful in technology development, the cost and efficiency of the second generation bioalcohols still needs to be optimized to overcome the high recalcitrance to enzymatic hydrolysis. In between, bioalcohol production from food and/or other municipal solid wastes can offer a synergistic solution to both problems. This chapter explains all the details about biochemical production of bioalcohols and specifically elucidates new technologies for bioethanol production.

Computer vision system approach in colour measurements of foods: Part II. validation of methodology with real foods

The colour of food is one of the most important factors affecting consumers’ purchasing decision. Although there are many colour spaces, the most widely used colour space in the food industry is L*a*b* colour space. Conventionally, the colour of foods is analysed with a colorimeter that measures small and non-representative areas of the food and the measurements usually vary depending on the point where the measurement is taken. This leads to the development of alternative colour analysis techniques. In this work, a simple and alternative method to measure the colour of foods known as “computer vision system” is presented and justified. With the aid of the computer vision system, foods that are homogenous and uniform in colour and shape could be classified with regard to their colours in a fast, inexpensive and simple way. This system could also be used to distinguish the defectives from the non-defectives. Quality parameters of meat and dairy products could be monitored without any physical contact, which causes contamination during sampling.

Use of Waste Bread to Produce Fermentation Products: Mehmet Melikoglu, Colin Webb

Abstract: Bread, the staple of the west and, increasingly, the rest of the world, is also one of the most heavily wasted of all food products. Currently, much of this waste is disposed of in landfill sites where it decomposes to methane and carbon dioxide. Yet it is a potentially valuable, renewable resource for the production of chemicals. This chapter explores the opportunities for enhancing the value of this cereal-based waste food through the use of fermentation. Following a review of the literature concerning bread waste utilization, potential process systems are proposed and examined. As bread is a solid raw material, solid state fermentation is preferred as the most efficient means of delivering bioprocesses, and some preliminary optimization studies are presented.