Biodegradable Antioxidant Composites with Almond Skin Powder.

Almond skin (AS) from industrial almond peeling is considered an agri-food waste with adequate composition to obtain composite films for food packaging due to its richness in polysaccharides, proteins, and phenolic compounds. Composite films based on amorphous polylactic acid (PLA) or partially acetylated polyvinilalcohol (PVA) were obtained by melt blending and compression moulding, incorporating different ratios of defatted AS powder (0, 5, 10, and 15 wt.%).

Active Polylactic Acid (PLA) Films Incorporating Almond Peel Extracts for Food Preservation.

Almond peel extracts, containing 0.2-0.8% (/) phenolic compounds with notable antioxidant and antimicrobial activities, could be used as a natural source of active compounds for the development of active films for food preservation.

Producing Aerogels from Rice Straw Cellulose Obtained by a Green Method and Its Starch Blending.

Cellulose and starch-cellulose composite aerogels were obtained using green cellulose from rice straw (RS) purified with a more environmentally friendly process. Pure starch aerogels were also obtained for comparison purposes. The effect of the aerogel cross-linking with polyamideamine-epichlorohydrin (PAE) was also analysed.

Biocomposites Based on PHBV and the Lignocellulosic Residue from Horchata Production.

The use of agro-industrial residues in the development of packaging materials is a topic of interest from a sustainable perspective, as it promotes biodegradability, reduces production costs, and aligns with the concept of a circular economy. The aim of this work was to develop and characterize biodegradable composite films based on Poly 3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and the tiger nut horchata solid residue (HSR) at different ratios. The obtained composites were evaluated as to their suitability as food active packaging materials in terms of microstructure, water content and solubility, mechanical, barrier and thermal properties, and total phenolic content and antioxidant capacity.

Applying Subcritical Water Extraction to Obtain Bioactive Compounds and Cellulose Fibers from Brewer Spent Grains.

Of the three types of waste generated in beer processing, brewer's spent grain (BSG) is the most abundant and has a high potential for valorization. In this work, defatted BSG (DB) was subjected to an extraction process with subcritical water at different temperatures to obtain extracts rich in phenols and the cellulosic fractions, which were also purified by using hydrogen peroxide (HO). The results showed that the dry extracts obtained at 170 °C were richer in phenolics (24 mg Gallic Acid Equivalent (GAE) g DB), but with lower antioxidant capacity (71 mg DB·mg 2,2-diphenyl-1-pikryl-hydrazyl).

Obtaining Cellulose Fibers from Almond Shell by Combining Subcritical Water Extraction and Bleaching with Hydrogen Peroxide.

Almond shell (AS) represents about 33% of the almond fruit, being a cellulose-rich by-product. The use of greener methods for separating cellulose would contribute to better exploitation of this biomass. Subcritical water extraction (SWE) at 160 and 180 °C has been used as a previous treatment to purify cellulose of AS, followed by a bleaching step with hydrogen peroxide (8%) at pH 12.

Active Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Films Containing Phenolic Compounds with Different Molecular Structures.

To obtain more sustainable and active food packaging materials, PHBV films containing 5% wt. of phenolic compounds with different molecular structures (ferulic acid, vanillin, and catechin) and proved antioxidant and antimicrobial properties were obtained by melt blending and compression molding. These were characterized by their structural, mechanical, barrier, and optical properties, as well as the polymer crystallization, thermal stability, and component migration in different food simulants.

Stability and Composting Behaviour of PLA-Starch Laminates Containing Active Extracts and Cellulose Fibres from Rice Straw.

The stability and composting behaviour of monolayers and laminates of poly (lactic acid) (PLA) and starch with and without active extracts and cellulose fibres from rice straw (RS) were evaluated. The retrogradation of the starch throughout storage (1, 5, and 10 weeks) gave rise to stiffer and less extensible monolayers with lower water vapour barrier capacity. In contrast, the PLA monolayers, with or without extract, did not show marked changes with storage.

Biodegradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) containing phenolic compounds in seawater in laboratory testing conditions.

Biodegradation in marine medium of PHBV films with or without 5 % wt. of phenolic compounds (catechin, ferulic acid, and vanillin) was assessed at laboratory scale. Respirometric analyses and film disintegration kinetics were used to monitor the process over a period of 162 days.

Production of Polyhydroxyalkanoates for Biodegradable Food Packaging Applications Using and Agrifood Wastes.

Polyhydroxyalkanoates (PHAs) are high-value biodegradable polyesters with thermoplastic properties used in the manufacturing of different products such as packaging films. PHAs have gained much attention from researchers and industry because of their biobased nature and appropriate features, similar to conventional synthetic plastics. This review aims to discuss some of the recent solutions to challenges associated with PHA production.

Circular Bioeconomy: Novel Processes and Materials for Food Preservation.

Food preservation is a set of procedures and resources aimed at blocking the action of external and internal agents that may alter the original characteristics of food [...

Subcritical Water Extraction for Valorisation of Almond Skin from Almond Industrial Processing.

Almond skin (AS) is an agro-industrial residue from almond processing that has a high potential for valorisation. In this study, subcritical water extraction (SWE) was applied at two temperatures (160 and 180 °C) to obtain phenolic-rich extracts (water-soluble fraction) and cellulose fibres (insoluble fraction) from AS. The extraction conditions affected the composition and properties of both valorised fractions.

Biodegradation of PLA-PHBV Blend Films as Affected by the Incorporation of Different Phenolic Acids.

Films based on a 75:25 polylactic acid (PLA) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) blend, containing 2% (/) of different phenolic acids (ferulic, -coumaric or protocatechuic acid), and plasticised with 15 wt. % polyethylene glycol (PEG 1000), were obtained by melt blending and compression moulding. The disintegration and biodegradation of the film under thermophilic composting conditions was studied throughout 35 and 45 days, respectively, in order to analyse the effect of the incorporation of the antimicrobial phenolic acids into the films.

Antimicrobial PLA-PVA multilayer films containing phenolic compounds.

Multilayer materials with good interlayer-adhesion were obtained by thermocompression for laminating an internal poly (vinyl alcohol) (PVA) layer with two external poly (lactic acid) (PLA) layers. Carvacrol or ferulic acid were incorporated into the PVA sheet to obtain active materials. The multilayer films were characterised as to their microstructure, thermal behaviour, tensile and barrier properties.

Biodegradable Antimicrobial Films for Food Packaging: Effect of Antimicrobials on Degradation.

The environmental problem generated by the massive consumption of plastics makes necessary the developing of biodegradable antimicrobial materials that can extend food shelf-life without having a negative impact on the environment. The current situation regarding the availability of biodegradable food packaging materials has been analysed, as well as different studies where antimicrobial compounds have been incorporated into the polymer matrix to control the growth of pathogenic or spoilage bacteria. Thus, the antimicrobial activity of active films based on different biodegradable polymers and antimicrobial compounds has been discussed.

Liposomal Encapsulation of Carvacrol to Obtain Active Poly (Vinyl Alcohol) Films.

Lecithins of different origins and compositions were used for the liposomal encapsulation of carvacrol within the framework of the development of active films for food packaging. Liposomes were incorporated into aqueous polymeric solutions from fully (F) and partially (P) hydrolysed Poly (vinyl alcohol) (PVA) to obtain the films by casting. The particle size distribution and ζ-potential of the liposomal suspensions, as well as their stability over time, were evaluated.

Application of Ultrasound Pre-Treatment for Enhancing Extraction of Bioactive Compounds from Rice Straw.

The extraction of water-soluble bioactive compounds using different green methods is an eco-friendly alternative for valorizing agricultural wastes such as rice straw (RS). In this study, aqueous extracts of RS (particles < 500 µm) were obtained using ultrasound (US), reflux heating (HT), stirring (ST) and a combination of US and ST (USST) or HT (USHT). The extraction kinetics was well fitted to a pseudo-second order model.

Polylactic acid-based materials encapsulating carvacrol obtained by solvent casting and electrospinning.

Polylactic acid (PLA) dissolved (15 wt.%) in ethyl acetate (EtAc): dimethyl sulfoxide (DMSO) binary systems (0:1; 1:3, and 2:3 v/v) was used as carrier to obtain carvacrol (CA)-loaded (20 wt.% with respect to PLA) matrices by electrospinning, in comparison with solvent casting.

The Incorporation of Carvacrol into Poly (vinyl alcohol) Films Encapsulated in Lecithin Liposomes.

Lecithin-encapsulated carvacrol has been incorporated into poly (vinyl alcohol) (PVA) for the purpose of obtaining active films for food packaging application. The influence of molecular weight (Mw) and degree of hydrolysis (DH) of the polymer on its ability to retain carvacrol has been analysed, as well as the changes in the film microstructure, thermal behaviour, and functional properties as packaging material provoked by liposome incorporation into PVA matrices. The films were obtained by casting the PVA aqueous solutions where liposomes were incorporated until reaching 0 (non-loaded liposomes), 5 or 10 g carvacrol per 100 g polymer.

Incorporation of natural antioxidants from rice straw into renewable starch films.

This study showed that rice straw waste is a valuable source for the extraction of water-soluble phenolic compounds that can be successfully incorporated into bioactive starch-based films. The major phenolic compounds in the extract were identified as ferulic, p-coumaric and protocatechuic acid using UHPLC-MS. Homogeneous films with antioxidant properties were produced by melt blending and compression molding and the changes in the physico-chemical properties were evaluated.

Encapsulation of eugenol by spray-drying using whey protein isolate or lecithin: Release kinetics, antioxidant and antimicrobial properties.

The encapsulation of eugenol (E) by spray-drying using whey protein (WP) or soy lecithin (LE) and maltodextrin in combination with oleic acid (OA) and chitosan (CH) was analysed in order to obtain antioxidant and antimicrobial powders for food applications. Formulations with only WP or LE showed higher encapsulation efficiencies (EE) (95-98%) and antibacterial effect against E. coli and L.

Antioxidant starch films containing sunflower hull extracts.

This study explores the preparation of antioxidant starch food packaging materials by the incorporation of valuable phenolic compounds extracted from sunflower hulls, which are an abundant by-product from food industry. The phenolic compounds were extracted with aqueous methanol and embedded into starch films. Their effect on starch films was investigated in terms of antioxidant activity, optical, thermal, mechanical, barrier properties and changes in starch molecular structure.

Release of polyphenols from starch-chitosan based films containing thyme extract.

The release kinetics of thyme extract polyphenols (TE) from chitosan (CH), pea starch (S) and CH:S blend films in different solvents was evaluated, as well as their antioxidant activity in each release media. Pure starch films showed the fastest delivery rate and the highest delivery ratio of polyphenols, although the corresponding release media exhibited the lowest antioxidant capacity. TE provided CH based films with remarkable antioxidant activity, despite the lower polyphenol release obtained in all solvents, due to the strong polyphenols-chitosan interactions.

Combination of Poly(lactic) Acid and Starch for Biodegradable Food Packaging.

The massive use of synthetic plastics, in particular in the food packaging area, has a great environmental impact, and alternative more ecologic materials are being required. Poly(lactic) acid (PLA) and starch have been extensively studied as potential replacements for non-degradable petrochemical polymers on the basis of their availability, adequate food contact properties and competitive cost. Nevertheless, both polymers exhibit some drawbacks for packaging uses and need to be adapted to the food packaging requirements.