Applications of lignin in the agri-food industry

Of late, valorization of agri-food industrial by-products and their sustainable utilization is gaining much contemplation world-over. Globally, 'Zero Waste Concept' is promoted with main emphasis laid towards generation of minimal wastes and maximal utilization of plantbased agri-food raw materials. One of the wastes/by-products in the agri-food industry are the lignin, which occurs as lignocellulosic biomass. This biomass is deliberated to be an environmental pollutant as they offer resistance to natural biodegradation. Safe disposal of this biomass is often considered a major challenge, especially in low-income countries. Hence, the application of modern technologies to effectively reduce these types of wastes and maximize their potential use/applications is vital in the present day scenario. Nevertheless, in some of the high-income countries, attempts have been made to efficiently utilize lignin as a source of fuel, as a raw material in the paper industry, as a filler material in biopolymer based packaging and for producing bioethanol. However, as of today, agri-food industrial applications remains significantly underexplored. Chemically, lignin is heterogeneous, bio-polymeric, polyphenolic compound, which is present naturally in plants, providing mechanical strength and rigidity. Reports are available wherein purified lignin is established to possess therapeutic values; and are rich in antioxidant, anti-microbial, anti-carcinogenic, antidiabetic properties, etc. This chapter is divided into four sub-categories focusing on various technological aspects related to isolation and characterization of lignin; established uses of lignin; proved bioactivities and therapeutic potentials of lignin, and finally on identifying the existing research gaps followed by future recommendations for potential use from agri-food industrial wastes.Theme of this chapter is based on our ongoing project- Valortech, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 810630

Lessening of high-pressure-induced changes in Atlantic salmon muscle by the combined use of a fish gelatin-lignin film

Salmon muscle is considerably affected by cooking with the resulting loss of its appealing red colour. The combined use of high pressure with fish gelatin-lignin film is proposed as an alternative to the more aggressive thermal processing procedures, with the aim of improving the appearance and overall quality of salmon fillets in ready-to-eat or semi-prepared dishes. The effects of high pressure processing (300. MPa, 10. min, 5 °C or 40 °C) and conventional heating (90 °C, 10. min) were evaluated in terms of colour changes, protein denaturation, as well as protein and lipid oxidation, by comparison with raw muscle. The stability of the processed products was assessed by monitoring changes in microbial growth and total volatile basic nitrogen and thiobarbituric acid reactive substances during 23. days of chilled storage. Fourier transform infrared spectroscopy (FTIR), apparent viscosity and dynamic oscillatory studies revealed notable differences in the overall degree and nature of protein aggregation between high pressure and heating treatments, especially when performed at 5 °C instead of 40 °C. SDS-PAGE of the protein fraction solubilised in 0.8. M NaCl showed MHC and α-actinin to be the main myofibrillar proteins denatured by high pressure processing at 40 °C, while actin was more denatured when pressurised at 5 °C. The film attenuated colour changes associated with high pressure treatment, especially at 5 °C, where redness was more preserved without jeopardising the appearance of a ready-to-eat product. High pressure processing at 5 °C in combination with gelatin-lignin film was found to improve protein quality of salmon fillets. The film reduced the levels of carbonyl groups formed immediately after processing, and prevented lipid oxidation from taking place at advanced stages of chilled storage. However, the effect on microbial growth was negligible, since total counts were similar for muscle with or without the film. © 2010 Elsevier Ltd.Peer Reviewe

Development of antimicrobial gelatin-ulvan-beeswax composite films: Optimization of formulation using mixture design methodology

A new generation of antimicrobial film was developed by incorporation of ulvan extracted from Ulva intestinalis into gelatin from common carp scale and its water sensitivity was reduced with addition of beeswax. Optimum composition of gelatin (0–100%w/w), ulvan (0–100%w/w) and beeswax (0–10%w/w) for achieving composite films with minimum water solubility (S) and water vapor permeability (WVP) and maximum tensile strength (TS), elongation at break point (EAB) and antibacterial effect on E. coli (EC) were investigated using mixture design methodology. Both pure gelatin and ulvan films and their composites had relatively good mechanical and optical properties. Addition of ulvan to gelatin produced composite films with good antibacterial properties but water resistance of all the films was weak. Addition of beeswax up to ∼5 % improved the water resistance and mechanical properties of the films without jeopardizing their antibacterial properties. The final optimum formulation with a desirability of 0.709 was achieved as 52.18 % of gelatin, 40.83 % of ulvan and 6.97 % of beeswax resulting in a minimum possible S (40 %) and WVP (1.86 10−10 g/ms Pa) and maximum possible TS (6.23 MPa) and EAB (89 %) with good EC (7.66 mm). Finally, good mechanical, thermal and microstructural properties of the optimum composite film was confirmed. Altogether, a combination of ulvan and beeswax can be a promising solution for development of gelatin films with both antimicrobial properties and lower water sensitivity

Effect of different concentrations of pure and mixed salt on the shelf life of salted rainbow trout (Oncorhynchus mykiss) roe during refrigerated storage

This study aimed to investigate the effects of salting of rainbow trout (Onchorhynchus mykiss) roe by pure and mixed salts (3.5, 4.5 and 5.5 %) on the quality and shelf life of the product, with respect to the contents of Total Volatile base nitrogen (TVBN), lipid oxidation (TBA), and on the proximate compositions during storage. The processing of roe leaded to changes in its chemical composition. In comparison with fresh roe, salted roe presented higher contents of TBA and lower content of TVBN. The greatest increases of TVBN were observed in the samples salted by salt without additives, in which TVBN was detected at 43.43 mg/100 g. pH value, salt absorption and TVBN and lipid oxidation had significant increase during storage (

Nutritional composition and antioxidant activity of vobla roach (Rutilus rutilus caspicus) muscle tissue exposed to heavy metals

The present study was carried out to study the toxic effects of different sublethal concentrations of cadmium chloride and lead salts [CdCl2 and Pb(NO3)2] on lipid, carbohydrate, protein contents and antioxidant enzymes of vobla-roach (Rutilus rutilus caspicus), a common Caspian fish species, in laboratory bioassays. R. rutilus caspicus was exposed to various sublethal concentrations of CdCl2 and Pb(NO3)2, i.e. 0.75, 1.5 and 2.25 mg L-1 for 24, 48, 72 and 96 hr. Then, the fishes were sacrificed and muscle was collected for the determination of carbohydrates, lipids, proteins, lipid peroxidation (LPO), catalase (CAT) and superoxide dismutase (SOD) activities. The results showed that the maximum decrease in lipid, carbohydrate and protein contents were observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (55.76%, 46.25% and 48.81%, respectively). Furthermore, antioxidant enzyme activities increased when fishes were exposed to cadmium and lead. The maximum increase in the lipid peroxidation and superoxide dismutase was recorded at 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (184.47 % and 110.52 %, respectively). According to the results, catalase activity decreased with increasing concentration of heavy metals and exposure duration. The maximum decrease in catalase activity was observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (81.21 %). In general, both heavy metals were highly toxic in muscle of R. rutilus caspicus, with lead showing higher toxicity then cadmium in terms of nutritional parameters and antioxidant enzyme activity

GAMMA-IRRADIATED ROSEMARY (ROSMARINUS OFFICINALIS) DIPS TREATMENT EFFECT ON QUALITY OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) FILLETS DURING REFRIGERATED STORAGE

The effect of the gamma-irradiated extract of rosemary and butylated hydroxyanisole (BHA) antioxidant on sensory, chemical and microbiological changes of rainbow trout fillets stored at 4 ± 1°C was investigated for 16 days. The fillets were divided into: control (C), 750 and 1500 rosemary extract (RE) (immersed in 750 and 1500 ppm rosemary extract); 250 and 500 gamma-irradiated rosemary (GIR), (immersed in 250 and 500 ppm gamma-irradiated rosemary) and 250 and 500 BHA (immersed in 250 and 500 ppm BHA). The shelf life of fillets was reported to be 8 days for C, and 12 days for 500 GIR group according sensory, microbiological and chemical parameters. The pH, peroxide value (PV), total volatile basic nitrogen (TVB-N), free fatty acid (FFA), thiobarbituric acid (TBA), psychrotrophic counts (PTC), and total viable aerobic bacterial counts (TVC) values were 7.62 ± 0.21, 17.17 ± 1.6, 51.07 ± 1.1, 6.05 ± 0.13, 3.42 ± 0.18, 12.03 ± 0.19, and 13.16 ± 0.16 respectively for C group and also, 7.42 ± 0.16, 15.2 ± 1.7, 42.5 ± 1.5, 4.48 ± 0.39, 2.59 ± 0.15, 9.98 ± 0.15, and 10.5 ± 0.15 respectively for 500 GIR group. Finally, the following trend in effectiveness was reported: gamma-irradiated rosemary PBS extract > BHA > rosemary PBS extract. © 2022, Trakia University. All rights reserved