Biorefinery concept in the meat industry: From slaughterhouse biowastes to superaborbent materials

The expansion of food production has a large environmental impact in many ways. More specifically, 30–40% of total food production is lost as wastes and/or by-products before it reaches the market. In this sense, blood is an inevitable by-product in the meat industry that typically consists of 3–5% of the total weight of the animal. The dry organic matter present in blood is mostly protein, which can be employed more efficiently as raw material in the development of biodegradable materials. In the present manuscript, the blood collected after slaughtering of Iberian pigs was centrifuged and the upper (i.e., plasma) and bottom (i.e., red cells) layers were separated. Three freeze-dried fractions were characterized and evaluated on terms of their potential in the field of bioplastics: whole blood, plasma and bottom layer. Albumin was detected clearly in the plasma fraction, while globulins in red cells. After their characterization samples were mixed thoroughly with glycerol and injection molded at 120 ◦C. Special applications may be proposed for every fraction (i.e., whole blood, plasma or red cells), as the materials displayed different properties depending on the raw material employed. Thus, plasma resulted in materials with a greater deformability and swelling capacity during immersion, resulting in superabsorbent materials when processed at milder conditions (80 ◦C)The authors acknowledge the projects PID2021-124294OB-C21 and PID2021-124294OB-C22 funded by MCIN/AEI/10.13039/ 501100011033/ and by “ERDF A way of making Europe” which sup- ported this study. K.C. and P.G. thank the Basque Government for BIOMAT funding (IT1658-22). The authors would like to thank the Spanish Ministerio de Universidades for the PhD grant PRE2019-089815 awarded to E. ´Alvarez-Castillo. The blood used was collected from a local slaughterhouse, Mataderos del Sur, S.A. Authors also would like to thank for kindly supplying the raw material employed in the study. The authors also acknowledge to the Microanalysis and Microscopy services from CITIUS (Universidad de Sevilla) for providing full access and assistance to equipment used

Nola erabili azpiproduktuak eta hondakinak, propietate egokiak dituzten material jasangarriak garatzeko?

Many studies have employed solution casting and compression moulding as processing methods to manufacture composites. Nevertheless, the commercial feasibility of soy protein-based biocomposites is directly related with the use of the techniques employed for processing synthetic polymers, such as extrusion and injection moulding. For that reason, those processing techniques were employed to develop soy protein based-biocomposites. Moreover, a natural waste obtained from the extraction of agarwas used as a filler. This waste showed good compatibility with soy protein and contributed to the development of more sustainable materials. These biocomposites showed good barrier and optical properties for packaging applications.; Ikerkuntza-lan askotan soluzio- eta konpresio- metodoak erabili ohi dira proteinetan oinarritutako konpositeak garatzeko. Hala ere, biokonposite berrien merkatu-bideragarritasuna, zuzen lotuta dago industria-aplikazio konbentzionalak garatzeko teknikekin, eta beraz, lan honetan estrusio eta injekziorako prozesatze-metodoak erabili dira, soja-proteinan oinarritutako biokonpositeak garatzeko. Bestalde, agarra erauzterakoan hondakin naturala lortzen da. Hondakin hau, biokonpositeen betegarri gisa erabili da. Betegarri honek, soja-proteinarekiko bateragarritasun ona erakutsi zuen, eta horrela biokonposite jasangarriagoak garatu dira. Biokonpositeen hesi-propietateak eta propietate optikoak egokiak izan ziren paketatze aplikazioetarako

Whey Protein Films for Sustainable Food Packaging: Effect of Incorporated Ascorbic Acid and Environmental Assessment

The management of food waste and by-products has become a challenge for the agri-food sector and an example are whey by-products produced in dairy industries. Seeking other whey valorisation alternatives and applications, whey protein films for food packaging applications were developed in this study. Films containing different amounts (0, 5, 10, and 15 wt%) of ascorbic acid were manufactured via compression-moulding and their physicochemical, thermal, barrier, optical, and mechanical properties were analysed and related to the film structure. Additionally, the environmental assessment of the films was carried out to analyse the impact of film manufacture. Regarding physicochemical properties, both FTIR and water uptake analyses showed the presence of non-covalent interactions, such as hydrogen bonding, between whey protein and ascorbic acid as band shifts at the 1500–1700 cm−1 region as well as a water absorption decrease from 380% down to 240% were observed. The addition of ascorbic acid notably improved the UV-Vis light absorbance capacity of whey protein films up to 500 nm, a relevant enhancement for protecting foods susceptible to UV-Vis light-induced lipid oxidation. In relation to the environmental assessment, it was concluded that scaling up film manufacture could lead to a reduction in the environmental impacts, mainly electricity consumption.The authors would like to thank Basque Government (KK-2021/00131 and IT1658-22) for its financial support

Developing active and intelligent films through the incorporation of grape skin and seed tannin extracts into gelatin

To achieve sustainability in the wine industry, by-products from winery operations are being diverted from waste streams and turned into beneficial use. Grape seed tannin (SeedT) and skin tannin (SkinT) extracts were used to modify the properties of gelatin films, and to prepare active/intelligent films. The SeedT extract showed a higher phenolic content (similar to 440 mg gallic acid (GA)/g extract) and antioxidant inhibition (similar to 20 %) than the SkinT extract (14 mg GA/g extract, 2 % antioxidant inhibition), while both extracts presented colour variations with an increase of solution pH. The addition of extracts into the gelatin formulation resulted in coloured and transparent films with lower wettability (water contact angle increased up to 92 degrees) and higher UV-light absorbance (secondary antioxidant function) properties. The films were capable of releasing tannins by up to 20 % which led to antioxidant inhibition values of up to 13 % (primary antioxidant function). The addition of SkinT tannins into the films provided the films with a pH indicator ability (intelligent function).The authors would like to thank the State Research Agency of Spain within the Juan de la Cierva - Incorporation action (IJC2019-039697I) and the Ministry of Business, Innovation and Employment (MBIE, Biocide Toolbox programme)

Arrain-hondakinak baloratzea, gazta ontziratzeko

Elikagaiak ontziratzeko filmak aztertzea garrantzitsua da, ikerketaren bidez gaur egun merkatuan dauden ontziratzeen propietateak hobetzea ahalbidetu baitaiteke. Kasu honetan, polimero berriztagarri eta biodegradagarri bat erabiliz, hainbat azido zitriko kantitatetako filmak egin dira. Haien propietateak aztertu dira, bai eta gazten ontziratzean duten jarrera. Arrain-gelatinazko film hauek film komertzialek eskaintzen ez dituzten zenbait propietate interesgarri erakutsi dituzte; esaterako, gaztak bere koipea gordetzea eta ez lehortzea ahalbidetzen dute

Electrospinning of Fish Gelatin Solution Containing Citric Acid: An Environmentally Friendly Approach to Prepare Crosslinked Gelatin Fibers

The majority of the crosslinking approaches employed to confer water resistance properties to electrospun gelatin mats are based on the use of potential cytotoxic agents, turning out to be not suitable for biomedical applications. Environmentally friendly chemical strategies based on the use of non-toxic agents are, therefore, strongly demanded. In the present work, the possibility to produce crosslinked electrospun fish gelatin mats by electrospinning an aqueous solution, containing citric acid as a crosslinking agent, is reported. The effect of pH on solution rheological properties, as well as on the electrospun mat morphology, chemistry, and crosslinking degree, is assessed. The increase of solution pH from 1.8 to 3.7 allows for obtaining fibers that maintain the fibrous morphology also in the mat. Subsequent thermal treatment of the electrospun mat (80 degrees C for 30 min) turns out to increase the crosslinking degree and morphological stability of the mat.This research was funded by the Spanish Ministry of Science, Innovation and Universities (RTI2018-097100-B-C22), the Basque Government (Department of Quality and Food Industry), the Provincial Council of Gipuzkoa (Department of Economic Development, the Rural Environment and Territorial Balance) and the Italian Ministry of University and Research (MIUR)

The Effect of Cross-Linking with Citric Acid on the Properties of Agar/Fish Gelatin Films

The aim of this work was to assess the effect of fish gelatin–citric acid nucleophilic substitution and agar–citric acid esterification reactions on the properties of agar/fish gelatin films. Since temperature is an important cross-linking parameter, films were treated at 90 °C and 105 °C and film properties were compared to those of non-cured films. It was observed that temperature favored the aforementioned reactions, which induced physical and morphological changes. In this regard, darker films with a rougher surface were obtained for the films with a higher cross-linking degree. While mechanical properties were slightly modified, the barrier properties were enhanced due to the reactions that occurred. Therefore, these agar/fish gelatin films cross-linked through two different reactions can be considered to be promising materials as active films for different purposes, such as active packaging or pharmaceutical applications.This research was funded by the Ministry of Science, Innovation, and Universities (RTI2018-097100-B-C22)

3D-Printed Mucoadhesive Collagen Scaffolds as a Local Tetrahydrocurcumin Delivery System

Native collagen doughs were processed using a syringe-based extrusion 3D printer to obtain collagen scaffolds. Before processing, the rheological properties of the doughs were analyzed to determine the optimal 3D printing conditions. Samples showed a high shear-thinning behavior, reported beneficial in the 3D printing process. In addition, tetrahydrocurcumin (THC) was incorporated into the dough formulation and its effect on collagen structure, as well as the resulting scaffold’s suitability for wound healing applications, were assessed. The denaturation peak observed by differential scanning calorimetry (DSC), along with the images of the scaffolds’ surfaces assessed using scanning electron microscopy (SEM), showed that the fibrillar structure of collagen was maintained. These outcomes were correlated with X-ray diffraction (XRD) results, which showed an increase of the lateral packaging of collagen chains was observed in the samples with a THC content up to 4%, while a higher content of THC considerably decreased the structural order of collagen. Furthermore, physical interactions between collagen and THC molecules were observed using Fourier transform infrared (FTIR) spectroscopy. Additionally, all samples showed swelling and a controlled release of THC. These results along with the mucoadhesive properties of collagen suggested the potential of these THC–collagen scaffolds as sustained THC delivery systems.This research was funded by MCI/AEI/FEDER, UE (RTI2018-097100-B-C22) and Provincial Council of Gipuzkoa

Physicochemical and Biological Performance of Aloe Vera-Incorporated Native Collagen Films

Collagen was obtained from porcine skin by mechanical pretreatments with the aim of preserving the triple helix structure of native collagen, which was indirectly corroborated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) results. Moreover, aloe vera (AV), with inherent biological properties, was incorporated into collagen film formulations, and films were prepared by compression and characterized to assess their suitability for biomedical applications. SEM images showed that the fibrillar structure of collagen changed to a rougher structure with the addition of AV, in accordance with the decrease in the lateral packaging of collagen chains observed by XRD analysis. These results suggested interactions between collagen and AV, as observed by FTIR. Considering that AV content higher than 20 wt % did not promote further interactions, this formulation was employed for biological assays and the suitability of AV/collagen films developed for biomedical applications was confirmed.This research was funded by the Basque Government, grant number KK-2019/00006

Evaluation of Bioactive Release Kinetics from Crosslinked Chitosan Films with Aloe Vera

Thermocompression was employed to prepare citric acid-crosslinked chitosan films with Aloe vera (AV) as bioactive compound. Films were easy to handle and mechanical properties did not change with the addition of AV up to 10 wt%, although both TS and EAB decreased for the films with 15 wt% AV, indicating that high AV contents would hinder intermolecular interactions among the formulation components. Maillard reaction occurred between chitosan and citric acid at the processing temperature used (115 °C), while physical interactions took place with AV, as shown by FTIR analysis. All films were insoluble but displayed hydration and limited swelling due to both physical and chemical interactions promoted by AV and citric acid, respectively. A slow AV release, governed by a Fickian diffusion controlled mechanism, and an increase of surface hydrophilicity, which favors cell adhesion, were observed.This research was funded by MCIU/AEI/FEDER, UE (RTI2018-097100-B-C22). Iratxe Zarandona thanks the Quality and Food Industry Department of the Basque Government for her fellowship (22-2018-00078