Presentation

Problem

When food waste is left in landfills it eventually turns into methane gas. Methane gas is 28 times more potent than carbon dioxide and after a decade it turns into carbon dioxide. This project looks at food waste from various industries, analyzes the important bioactive compounds found in them and the potential of extracting them using various techniques.

So with this considered, I will be trying to answer the question:

What would be an effective way of keeping food waste from landfills other than composting?

Method

Research food waste decay rate in landfills and efficiency of gas collection systems in capturing the methane emissions from food waste.
Analyse different sources of food waste from major food industries.
Examine the different food valorization techniques in converting food waste into useful bioactive compounds.

Research

Background Research

30 to 40% of the food produced by farmers globally, is never consumed.
At the manufacturing level, more than 10% of food is wasted due to human errors.
About 30% of food is thrown away by grocery stores
The annual value of food wasted worldwide is one trillion dollars

Percentage of food waste generated at various levels of food supply chain in America

Landfill systems

It is mandatory for landfills to install gas collection systems within five years to capture methane gas being produced in landfills. Most food wastes produced are not composted rather they are taken in landfills where they turn into methane gas.

Decay rate of various organic materials

The decay rate is a first order reaction – the higher the rate, the faster the decay. For example, food waste has a decay rate of 0.19 means that half of the carbon has been degraded to methane in 3.6 years.

Efficiency of collection systems

An estimated 61 percent of methane generated by food waste avoids collection by landfill gas collection systems. They become fugitive emissions (i.e., is released to the atmosphere)

The increase in the amount of methane emitted from food waste is due to:
- Food waste emissions occur earlier and landfill operators are collecting more gas later in the landfills lifetime than earlier.
- Thus, for materials like biodegradable textiles, paper products, and wood, which degrade more slowly, more of the landfill gas is collected.

Sources of food waste

Waste from different industries

Data

Food valorization techniques

Novel approaches to circulate waste by producing bio-active compounds

Supercritical fluid extraction

Supercritical fluid extraction (SFE) is a process that uses supercritical fluids, such as carbon dioxide (CO2), to extract desirable compounds from various substances. In the context of food waste, SFE with CO2 can be a valuable technique for extracting valuable compounds from food waste streams, thereby reducing waste and potentially obtaining useful products.

Raw material	Extraction Conditions	Compound
Apricot, sweet potato, red tomato, pumpkin and peach peels; green, yellow and red bell peppers and their waste residues (seeds and stems) Grape peel Banana peel Yarrow and rosehip herbal dust, and their mixture	59 C; 350 bar; 15.5% of ethanol; 30 min; flow rate of 15 g min1 37–46 C; 137–167 bar; 5%–8% of ethanol; 30 min; flow rate of 2 mL min1 40–50 C; 100–300 bar; 220 min; flow rate of 5 g min1 40 and 60 C; 100–300 bar; 5 h; flow rate of 0.194 kg h1	Carotenoids
Orange peel	35.86–64.14 C; 82.7–333.7 bar; 90 min	Terpenes
Broccoli stem and leaves	443 bar, 40 °C, 31 g/min	β-carotene, chlorophylls, phytosterols, and phenolic compounds
Tomato waste, seeds and skins	150 bar, 20 °C, and 5 mL/min	Lycopene 205 mg per 100 g and β-carotene 75 mg per 100 g of extracted oleoresin

Subcritical water extraction

Referred to as high-temperature and high-pressure water is subcritical water. Useful and unique characteristics of subcritical water, its polarity can be dramatically decreased with increasing temperature. Meaning subcritical water can behave similar to methanol or ethanol. Making subcritical water a green extraction fluid used for a variety of organic species.

Compound

Raw material

Extraction condition

Polyphenols

Potato peel

Grape skin

Red grape pomace

Pumpkin leaves

Spent coffee grounds

Apple by-products

Onion skin

Wheat straw

100–240 C; 60 bar; 30–120 min

100–160 C; 100 bar; 40 s

40–140 C; 68 bar

100–220 C; 10–50 min

160–180 C; 35–55 min

25–200 C; 103 bar; 3–17 min

170–230 C; 30 bar; 30 min

130–270 C; 1.7–54 bar; 10 and 30 min

Carbohydrates

Spent coffee ground

Citrus peel and apple pomace

Sugar beet pulp

Peach pomace

Onion bulbs and skins

Peanut shell

Corn stalks

150–210 C; 20–60 bar; 5–15 min

100–140 C (citrus peel) and 130–170 C (apple pomace); 5 min

110–130 C; 80–120 bar; 20–40 min

40–80 C; 10–80 min;

99.8–319.8 C; 5 min

180–240 C; 60–480 s

280–390 C; 25–40 s

Proteins and amino acids

Shrimp cephalothorax by-products

Waste fish entrails

Okara

Deoiled rice bran

Mackerel liquid waste

230–280 C; 27.8–201.8 bar; 5–30 min

19.8–449.8 C; 350 bar; 90 min; flow rate of 40 cm3/min

70–260 C; 2–120 min

100–220 C; 1.03–39.7 bar; 0–30 min

90–190 C; 50 bar; 1 or 2.5 h

Oils and fatty acids

Squid by-product entrails

Olive pomace

Rice bran

169.8–379.8 C; 7.92–300 bar; 1–40 min

160–200 C; 5–25 bar; 260–350 s

120 and 240 C; 10 and 20 min

Ultrasound extraction

Ultrasound-assisted extraction produces a phenomenon known as cavitation, which entails the production, growth and collapse of bubbles, leading to improved release of the target compounds from several natural sources.

Fruit source:	Target compounds:	Extraction conditions:
Grape pomace	Phenolics	20–60 °C, Amplitude 20–60 %, LS 8–24 mL/g, 240 min
Sichuan red orange peel	Tangeretin & nobiletin	Ethanol 85 %, LS 20:1 mL/g, 40 min, 50 °C, 150 W, 20 kHz
Mandarin peel	Phenolic content	48 °C, 56.71 W, 40 min, 38.5 kHz
Mandarin peels	Pectin	80 °C, 37 kHz, 30 min
Orange peel	Carotenoids	35 min, 42 °C, LS 15 mL/g
Orange peels	Antioxidants	30 min, 60 °C, 15 mL/g

Microwave assisted extraction

This method uses microwave energy, heating the solvent within the sample, which accelerates the extraction process by the release of target compounds from the biomass matrix.

Sources:	Compounds:	Temperature:	Solvent/Co-solvent
Vine prune residues	Total phenolic content	120	Ethanol -water
Ocimum basilicum	Polyphenols	-/442	Ethanol
Mangifera indica leaves	Mangiferin	-/272	Water
Red grape pomace	Phenolics	50/200	Water-ethanol
Cabbage leaves	Phenolic content	~50/100	Ethanol

Conclusion

My research has shown that numerous bioactive compounds can be derived from food waste.

Various advantages are provided by these methods
- Reducing waste
- Create new economic prospects and promote a circular economy
- Develop functional food ingredients, cosmetics, and dietary supplements.

Limitations of these techniques:
- Most techniques are in their early stages of development
- Excessive extraction costs due to expensive equipment, solvents, and energy being a significant obstacle.

Undesirable extraction rates,

Advancements needed in this technology:
- Improve the efficiency of the extraction processes
- Develop new methods that are more environmentally friendly
- Use of more green solvents

Ultimately, the goal of the project is to find alternate ways other than compositing and breathe new life into waste with the background of the urgent problem of global FW production as a driving force. Going forth from this, the next steps of this project would be to advance and expand on this topic, channeling food waste to factories where food waste is utilized to make new products.