Hydrophobic Starch-Based Films Using Potato Washing Slurries and Spent Frying Oil

Sustainable valorisation of bioactive molecules from rice husks through hydrothermal extraction for chitosan-based bioplastic production

Rice husks are a low value byproduct, even though it possesses molecules with great potential, such as arabinoxylans, proteins, and silica. These molecules can be used to improve mechanical and physicochemical properties of materials for food packaging. In this work, hydrothermal treatment was used for a sustainable extraction of the valuable molecules present in rice husks. Various extraction temperatures (180, 200, and 220 °C) were performed targeting to extract fractions with distinct compositions. The water extract obtained at 220 °C demonstrated the highest extraction yield, 3 times superior to conventional hot water extraction. These extracts exhibited high content of proteins, phenolic compounds, and carbohydrates, particularly arabinoxylans. This extract was incorporated in chitosan-based films in different ratios, 1:0.1, 1:0.3, and 1:0.5 (chitosan:extract, w:v). The film with the lowest extract ratio presented the highest flexibility (higher elongation and lower Young's modulus) when compared to the pristine chitosan film. The antioxidant capacity was also increased, achieving an antioxidant capacity of >10-fold in comparison to control film. The results revealed that hydrothermal extraction emerges as an environmentally friendly and sustainable methodology for extracting valuable compounds from rice industry byproducts. This method exhibits significant potential to impart flexible and antioxidant properties to biobased materials.

Exploring novel organocatalytic-acetylated pea starch blends in the development of hot-pressed bioplastics

Acetylated starch shows enhanced thermal stability and moisture resistance, but its compatibilization with other more hydrophilic polysaccharides remains poor or unknown. In this study, the feasibility of thermomechanically compounding organocatalytically acetylated pea starch (APS), produced at two different degrees of substitution with alkanoyl groups (DSacyl, 0.39 and 1.00), with native pea starch (NPS), high (HMP) and low methoxyl (LMP) citrus pectin, and sugar beet pectin (SBP, a naturally acetylated pectin) for developing hot-pressed bioplastics was studied. Generally, APS decreased hydrogen bonding (ATR-FTIR) and crystallinity (XRD) of NPS films at different levels, depending on its DSacyl. The poor compatibility between APS and NPS or HMP was confirmed by ATR-FTIR imaging. Contrariwise, APS with DSacyl 1 was effectively thermomechanically mixed with the acetylated SBP matrix, maintaining homogeneous distribution within it (ATR-FTIR imaging). APS (any DSacyl) significantly increased the visible/UV light opacity of NPS-based films and decreased their water vapor transmission rate (WVTR, by ca. 11 %) and surface water wettability (by ca. 3 times). In comparison to NPS-APS films, pectin-APS showed higher visible/UV light absorption, tensile strength (ca.2.9-4.4 vs ca.2.4 MPa), and Young's modulus (ca.96-116 vs ca.60-70 MPa), with SBP-APS presenting significantly lower water wettability than the rest of the films.

Quality Characteristics of Raspberry Fruits from Dormancy Plants and Their Feasibility as Food Ingredients

The raspberry (Rubus idaeus L.) is a soft red fruit consumed worldwide due to its bitter-sweet taste and phenolics-associated health benefits. During plant dormancy, raspberry fruits are discarded. However, this work hypothesised that these fruits have the chemical quality to be valorised, which would mitigate their waste if adequately stabilised. This can be achieved by drying. The Pacific Deluxe and Versailles varieties were dried by freeze- and convective-drying (30 °C and 40 °C). The freeze-dried fruits preserved their colour, drupelets structure, and phenolic content. Convective-drying promoted a significant fruit darkening, which was more evident at 30 °C due to the longer drying process, and a loss of drupelets structure. Both temperatures promoted a similar decrease in phenolic content, as determined by HPLC, although the ABTS●+ antioxidant activity at 40 °C was lower (IC50 = 9 compared to 13 μg AAE/mg dry weight). To incorporate dried raspberries into muffin formulations, while keeping their red colour, it was necessary to change the raising agent from sodium bicarbonate to baker's yeast. Sensory analysis by a non-trained panel revealed good acceptance, showing that fresh or dried raspberry fruits from dormancy had suitable characteristics for use as food ingredients.

Preparation and characterization of self-standing biofilms from compatible pectin/starch blends: Effect of pectin structure

Pectin structure-miscibility-functionality relationships in starch films remain unknown. In this study, five citrus pectins (CPs) with 17 to 63 % of degree of methyl esterification (DM) and sugar beet pectin (SBP, rich in acetyl moieties and rhamnogalacturonan-I domains) were investigated for composition and structure and, further, blended with pea starch (3:1 starch-pectin weight ratio) to fabricate self-standing films. The incorporation of pectin resulted in a two- to three-fold increase in tensile strength and Young's modulus (up to 52.2 and 1837 MPa, respectively, using CP with low DM) without compromising elongation at break. Starch-SBP films presented the lowest strength among pectin films. Lower film moisture and water vapor permeability were attained with CP of high DM, or with SBP, whereas surface wettability was explained by counteracting factors affecting film compositional heterogeneity. Films made with high methoxyl CP, or with SBP, showed lower overall H-bonding (FTIR) and starch crystallinity (XRD). A DM above 57 % negatively affected the mixing and interfacial adhesion of pectin with starch, as shown by Attenuated Total Reflection-FTIR imaging. Pectins with the lowest purity, presumably with the greatest content in xyloglucan, as suggested by HPAEC, presented ~20 % higher elongation at break than the other films.

Effect of Biobased Cling Films on Cheese Quality: Color and Aroma Analysis for Sustainable Food Packaging

Biobased and biodegradable polymeric materials are a sustainable alternative to the conventional plastics used in food packaging. This study investigated the possible effect of biobased cling films derived from renewable and circular and sustainable sources on key cheese sensory parameters (appearance and odor) able to influence consumer acceptance or rejection of a food product over time. For this purpose, a semi-hard cheese was selected as food model and stored for 14 days at 5 °C wrapped with five cling films: two bio-plastic materials from renewable circular and sustainable sources (R-BP1 and R-BP2), one bio-plastic film from a non-renewable source (NR-BP), and two conventional cling films (LDPE and PVC). Three analytical approaches (image analysis, electronic nose, and sensory test) were applied to evaluate the variation and the acceptability in terms of appearance and odor of the cheese. In preserving cheese color, the R-BP1 and RBP2 films were comparable to LDPE film, while NR-BP film was comparable to PVC film. In terms of odor preservation, R-BP2 film was comparable to LDPE and PVC. The consumer test showed that appearance and odor scores were higher for cheeses stored in R-BP1 and R-BP2 films than NR-BP film. Moreover, in terms of odor, R-BP1 film performed better than conventional films. This study shows how biodegradable cling films from renewable circular and sustainable resources could have comparable performance to conventional plastics (LDPE and PVC) used in the food sector.

Sustainable and Bio-Based Food Packaging: A Review on Past and Current Design Innovations

Food loss and waste occur for many reasons, from crop processing to household leftovers. Even though some waste generation is unavoidable, a considerable amount is due to supply chain inefficiencies and damage during transport and handling. Packaging design and materials innovations represent real opportunities to reduce food waste within the supply chain. Besides, changes in people's lifestyles have increased the demand for high-quality, fresh, minimally processed, and ready-to-eat food products with extended shelf-life, that need to meet strict and constantly renewed food safety regulations. In this regard, accurate monitoring of food quality and spoilage is necessary to diminish both health hazards and food waste. Thus, this work provides an overview of the most recent advances in the investigation and development of food packaging materials and design with the aim to improve food chain sustainability. Enhanced barrier and surface properties as well as active materials for food conservation are reviewed. Likewise, the function, importance, current availability, and future trends of intelligent and smart packaging systems are presented, especially considering biobased sensor development by 3D printing technology. In addition, driving factors affecting fully biobased packaging design and materials development and production are discussed, considering byproducts and waste minimization and revalorization, recyclability, biodegradability, and other possible ends-of-life and their impact on product/package system sustainability.

Synergizing Multi-Plasticizers for a Starch-Based Edible Film

Synergized multi-plasticizers for a starch-based edible film were developed for food packaging. The most popular edible plasticizers, water, glycerol, and sorbitol were used as modal materials to demonstrate the synergized function of multi-plasticizers. The efficiency, stability, and compatibility of each plasticizer, as well as their synergized functions were investigated based on the characterizations of tensile properties after storing under different humidity conditions and for different times. The relationship between the microstructures of the plasticizers and their performances was studied and established. The results showed that water is an efficient plasticizer but is not stable, which results in it becoming brittle under lower humidity conditions; glycerol has a stronger moisture-retaining and absorption capability, which results in a weaker tensile strength under higher humidity conditions; and sorbitol is an efficient and stable plasticizer but needs to work with water, and its function can be synthesized by mixing it with water and glycerol.