Biorefinery cascade processing for creating added value on tomato industrial by-products from Tunisia

Abstract

BackgroundIn today’s consumer perception of industrial processes and food production, aspects like food quality, human health, environmental safety, and energy security have become the keywords. Therefore, much effort has been extended toward adding value to biowastes of agri-food industries through biorefinery processing approaches. This study focused, for the first time, on the valorization of tomato by-products of a Tunisian industry for the recovery of value-added compounds using biorefinery cascade processing.ResultsThe process integrated supercritical CO2 extraction of carotenoids within the oil fractions from tomato seeds (TS) and tomato peels (TP), followed by a batch isolation of protein from the residues. The remaining lignocellulosic matter from both fractions was then submitted to a liquid hot water (LHW) hydrolysis. Supercritical CO2 experiments extracted 5.79% oleoresin, 410.53 mg lycopene/kg, and 31.38 mg β-carotene/kg from TP and 26.29% oil, 27.84 mg lycopene/kg, and 5.25 mg β-carotene/kg from TS, on dry weights. Protein extraction yields, nearing 30% of the initial protein contents equal to 13.28% in TP and 39.26% in TS, revealed that TP and TS are a rich source of essential amino acids. LHW treatment run at 120–200 °C, 50 bar for 30 min showed that a temperature of 160 °C was the most convenient for cellulose and hemicellulose hydrolysis from TP and TS, while keeping the degradation products low.ConclusionsResults indicated that tomato by-products are not only a green source of lycopene-rich oleoresin and tomato seed oil (TSO) and of protein with good nutritional quality but also a source of lignocellulosic matter with potential for bioethanol production. This study would provide an important reference for the concept and the feasibility of the cascade fractionation of valuable compounds from tomato industrial by-products.Graphical abstractSchema of biorefinery cascade processing of tomato industrial by-products toward isolation of valuable fractions.

Development of a tomato pomace biorefinery based on a CO2-supercritical extraction process for the production of a high value lycopene product, bioenergy and digestate

“…for the S exh and A exh respectively that corresponded to an average biodegradability increase of 64%. This result agreed with previous works that described an increase of fibre availability measured as sugars-free fraction (Kehili et al, 2016).Ionic liquid (IL) was already able to improve fibre biodegradability, however exhaust biomass was IL polluted and unusable as AD feedstock (Allison and Simmons, 2017). On the contrary, SFE-CO 2 gave exhaust biomass solvent-free, dried and sterilised, characteristics that improved TP exh reusability respect to the TP raw .…”

“…The extracts' antioxidant power depended on the TP rawIM content and on the extraction process that was carried out at high temperature to increase lyc recovery while destroying other thermolabile molecules, a process which might have decreased the antioxidant properties (Shi and Maguer, 2000;Vàgi et al, 2007;Egydio et al, 2010;Liu et al, 2011;Kehili et al, 2016;Mutsokoti et al, 2017).…”

“…Developing a complete biorefinery aims to maximise productions applying a series of processes by using the exhaust fraction as feedstock. To our knowledge, only two scientific papers have explored this possibility (Kehili et al, 2016;Allison et al, 2017) for TP and encouraging results were obtained when SFE-CO 2 was the first production step since the exhaust fraction is solvent-free and dried, therefore easily employable.…”

Tomato value chain analysis in Tunisia : business opportunities : Business opportunities

“…Waste of tomatoes can be used for bulk juices and natural dyes. Results indicated that tomato byproducts are not only a green source of lycopene-rich oleoresin and tomato seed oil (TSO) and of protein with good nutritional quality but also a source of lignocellulosic matter with potential for bioethanol production [26].…”

Upgrading of Tomato (Solanum lycopersicum) Agroindustrial Wastes

“…Thus Egypt has huge amounts of tomato crop residues and agroindustrial wastes; leaves, stems, pomace (skin, seeds and pulps). Tomato Agroindustrial Wastes (TAW) could be used for producing different valuable products, such as carotenoids, proteins and it can be used also as a potential feedstock for ethanol production not only because of their low cost and high availability but also because of their considerable amount of sugars and low content of lignin [5].…”