Hemolytic uremic syndrome associated with Shiga toxin-producing Escherichia coli (STEC-HUS) infection is a major individual and public health challenge, and the leading cause of acute kidney injury in children. In Western countries, HUS complicates about 15
In recent years, biocontrol agents (BCAs) have gained attention as sustainable alternatives or complements to synthetic chemicals for managing phytopathogens and enhancing plant growth. In this study, six bacterial strains were evaluated as BCAs against Rhizoctonia solani (RS), a soil-borne pathogen affecting economically important crops. Two strains (Bacillus sp. B04A33 and Psychrobacillus sp. B04A42) were isolated from maize embryos, while Lactiplantibacillus plantarum strains (ITEM 17215, ITEM 17218, ITEM 18335 and S61) originated from food or animal sources. A commercial Trichoderma-based product (REMEDIER®, Gowan Italia) served as the control. Biocontrol effectiveness was assessed both in vitro and in vivo on lettuce using an automated imaging system for plant growth monitoring. In soils infected by R. solani, the inoculum of strains B04A33, B04A42, and S61 enhanced germination and seedling vigor, and increased dry weight of shoots and roots. Root system development, analyzed via image processing in Matlab, confirmed improved growth. The qPCR analysis of soil samples showed that microbial abundance increased in non-treated (NT) and S61 + RS treatments, while R. solani levels decreased in B04A33 + RS and B04A42 + RS. Oxford Nanopore MinION sequencing of soil samples revealed dominance of Pseudomonadota, Actinomycetota, and Bacillota, with enrichment of Bacillaceae and Lactobacillaceae in B04A42 and S61 treatments, confirming the successful establishment of the inoculated strains within the soil microbiome. These results support both the potential of selected bacterial strains as effective BCAs against RS and the use of automated imaging in BCAs screening procedures, promoting sustainable and technology-assisted crop management.
Legumes are sustainable and nutritionally valuable crops, yet their consumption is limited by antinutritional factors including lectins, phytic acid, and raffinose-family oligosaccharides (RFOs) impairing nutrient absorption and causing gastrointestinal discomfort. The study investigates the development of bread enriched with 25% fermented common bean (Phaseolus vulgaris L.) flour by exploiting lactic acid bacteria (LAB) fermentation from three different strains: Lentilactobacillus buchneri LBC01, Lacticaseibacillus rhamnosus LRH01, and Leuconostoc lactis LN01. Antioxidant activity and digestibility, but also technological aspects, including dough rheology, loaf volume, volatile organic compound profile, and shelf-life, were evaluated. Notably, LAB fermentation improved dough leavening and reduced staling within 24 h, enabling a higher incorporation of legume flour. Ln. lactis increased bread volume by 15% compared to Saccharomyces cerevisiae. RFOs were not detected in either the fermented flours or the resulting breads. The inclusion of fermented bean flour significantly enhanced antioxidant capacity, with radical scavenging activity nearly tenfold higher than that of the wheat bread. Analysis of volatile compounds showed that enriched bread exhibited the highest overall volatile content. 2-pentylfuran-associated with "beany" aroma-was elevated in breads containing fermented bean flour (FBF), while diacetyl and acetoin (contributing buttery and caramel notes) were most abundant in breads fermented with L. rhamnosus. Microbial proteolysis contributed to improved protein digestibility, and FBF breads also showed increased starch hydrolysis. Overall, LAB fermentation offers a viable approach for producing legume-enriched breads with superior nutritional quality, improved technological performance, and extended shelf life, while effectively mitigating common challenges associated with the use of legume-based ingredients.
Cereals are rich in nutrients and bioactive compounds; however, many of these, such as polyphenols, are bound to the cell wall matrix, limiting their bioavailability. This study investigated the use of fermentation to enhance the bioavailability of functional compounds in whole-wheat flour. Given the impact of microbial species on fermentation outcomes, various combinations of lactic acid bacteria and yeast strains were examined. The polyphenol and flavonoid content of different fermented flours was analyzed. Additionally, the antioxidant capacity was assessed using in vitro assays (DPPH, ORAC, and FRAP) and an ex vivo test with human erythrocytes. Fermentation significantly enhanced the release of bioavailable phenolic compounds and flavonoids, with the most significant increases reaching up to 3.4-fold and 2.64-fold, respectively. In particular, the findings highlight the capacity of flour fermented with a combination of K. humilis, F. sanfranciscensis, E. faecium, P. pentosaceus, and L. mesenteroides to enhance antioxidant activity in vitro and to protect human red blood cells from oxidative stress. Furthermore, fermentation increased the production of short-chain fatty acids, notably lactate and acetate, which are widely recognized for their gut health benefits. Overall, this study highlights the effectiveness of targeted fermentation in improving the bioactivity and antioxidant properties of whole-wheat flour.
Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) exhibits relevant probiotic and technological features and is widely used in food industries, improving flavour, texture and organoleptic properties of fermented products. Cell-surface proteins have a key role in the molecular mechanisms responsible for healthy effects, being the first actors in the bacteria - host interactions. Proteins present on the surface of four L. plantarum strains (two isolated from vegetable matrices and two from dairy products) were identified by proteomics with the aim to gain a comprehensive picture of differences in protein profiles potentially related to the habitat of origin and specific properties of the analyzed strains. Results highlighted a more diversified pattern of surface proteins in strains from vegetable matrices compared to those from dairy matrices (>500 proteins vs about 200 proteins, respectively). The four strains shared a core of 143 proteins, while 445 were specifically present in strains from vegetable matrices and 26 were peculiar of strains from dairy origin. Sortase A, involved in adhesion, and choloylglycine hydrolase (bile salt hydrolase) were detected only in strains from vegetable matrices. The peculiar molecular functions of identified proteins suggested that these strains, and in particular L. plantarum S61, could have a significant probiotic and biotechnological potential.
In the Alpine region of Austria, Italy, and Switzerland, transhumance is widespread and the production of local traditional dairy products during summer is important. Raw milk cheeses are produced according to traditional recipes, using hurdles as a technique to guarantee food safety. In the present study, we aim to provide an overview of S. aureus and its enterotoxins in raw milk cheeses, identify the key parameters responsible for the enterotoxin production, and identify ways to improve food safety. The results demonstrate that safe artisanal raw milk cheese production is achievable under elementary conditions by applying effective hurdles, including high scalding temperatures or thermization, quality starter cultures, and robust milk quality management. The hurdle index (HI), which we introduce in this paper, is a promising tool for assessing and improving safety in raw milk cheese production.
Lactic acid bacteria (LAB) can produce bacteriocins that exert an antimicrobial activity against Clostridium spp. responsible for late blowing defects (LBD) in cheese. This study aimed to evaluate the influence of cheese-making and ripening temperature and salt concentration on the LAB bacteriocin production to enable their effective use in dairy chain.Five Lactococcus strains (Lc. cremoris FT27 and Lc. lactis N16, N26, SV77 and VC106) with anti-Clostridium activity were selected for their ability to produce bacteriocin at the optimal growth temperature (30 °C) and in temperature conditions resembling those of the uncooked and semi-cooked cheese-making. At optimal growth condition the bacteriocin titre resulted to be strain-dependent (from 2.4 to 3.3 log10 IU/mL), differently at temperatures applied during the cheese-making process only one strain (Lc. lactis VC106) was able to produce a high amount of bacteriocins (2.8 and 2.9 log10 IU/mL, respectively. During the period that simulated the ripening process at 10 °C, the bacteriocin titre of Lc. lactis VC106 declined progressively (1.6 and 1.9 log10 IU/mL after 170 days), but remained above the threshold required to inhibit the LBD. Our findings provide new evidence of how cheese-making and ripening processes adversely affect the bacteriocins synthesis and, consequently, the anti-Clostridium activity. Lc. lactis VC106 showed an antimicrobial activity comparable to that obtained at optimal growth temperature suggesting that this strain could provide a useful tool to inhibit spoilage bacteria in the dairy chain.
Bovine mastitis is a major challenge in dairy farms. Since the agents commonly used for pre- and post-dipping can affect the udder health by modifying milk microbiota, alternative products are needed. This study aimed to evaluate the effect of the use of pre- and post-dipping formulations containing the fermented broth of Nisin A-producing Lactococcus cremoris FT27 strain (treated group, TR) on the abundance and biodiversity of milk microbiota as compared to iodine-based commercial disinfectants (control group, CTR) during a three-month trial. The experiment was conducted on 20 dairy cows, divided into two groups (CTR and TR) of 10 lactating cows each. Milk samples were collected from two selected healthy quarters of each cow at 3 time-points. Microbial communities were investigated by cultural and sequence-based methods, and analyzed through bioinformatic and statistical approaches. Clear differences in bacterial community composition were observed among groups, with higher species richness in TR, especially of Staphylococcus, Enterococcus, Lactococcus, and Streptococcus genera. The microbiota was dominated by Firmicutes, followed by Actinobacteriota, Proteobacteria, and Bacteroidota. Staphylococcaceae family was significantly higher in TR (p < 0.009), whereas Carnobacteriaceae, Mycobacteriaceae, and Pseudomonadaceae were significantly lower (p = 0.005, p = 0.001, and p = 0.040, respectively). CTR had considerably higher abundances of the genera Alkalibacterium (p = 0.011), Pseudomonas_E (p = 0.045), Corynebacterium (p = 0.004), and Alloiococcus (p = 0.004), and lower abundances of Staphylococcus (p < 0.009). Milk microbiota changed noticeably during the experimental period, regardless of treatment. A significant decrease was observed in both groups for Firmicutes_A phylum, with an increment in Actinobacteriota phylum, Propionibacteriaceae family, and Cutibacterium genus. Streptococcaceae significantly decreased in CTR (p = 0.013) and rose in TR (p = 0.001). Several differences were observed between the two groups during the experimental period. Streptococcus genus almost disappeared in CTR (p = 0.013), whereas it significantly increased in TR (p = 0.001). Three and twelve enriched groups were significantly identified respectively in CTR and TR using LEfSe. The use of Nisin A-based teat dip formulations could be linked to greater microbial diversity compared to commercial products. Despite the influence of seasonality, the experimental formulations maintained higher milk biodiversity, suggesting that lactic acid bacteria metabolites prevent alterations in the milk microbiota.
This study aimed to verify, under real operating conditions, the effectiveness of protective lactic acid bacteria (LAB) culture in counteracting the development of late blowing defects in Valtellina Casera PDO cheese and its impact on product sensory characteristics. Thirty-four LAB isolated from Bitto and Valtellina Casera PDO cheeses were screened for anti-Clostridium activity. Lacticaseibacillus casei VC201 was able to inhibit all the indicator strains through organic acid production. Valtellina Casera PDO cheese-making was performed twice in three dairy farms using a commercial autochthonous starter culture with and without the addition of the protective culture VC201. Cheese was ripened both at 8 °C and 12 °C and analyzed after 70 and 180 days for LAB population, proteolysis, and lipolysis evolution as well as sensory impact. Cheeses with the addition of the VC201 strain showed higher contents of rod-shaped LAB throughout the ripening at both temperatures. The protective culture decreased the production of butyric acid at 70 days, especially at 8 °C (−15.4%), while butyric fermentation was occasionally lightly observed at 12 °C. The sensory profile was favorably impacted by the higher relative proportion of short-chain fatty acids (SCFFAs, C2–C8), which was especially pronounced at 8 °C and persisted for 180-day ripening (23.91% vs. 18.84% at 70 days and 23.84 vs. 21.71 at 180 days of ripening). The temperature and time of ripening had a significant effect on the free fatty acid content of the cheese samples in all three classes (SCFFA, MCFFA, and LCFFA). The cheese made with Lcb. casei VC201 was preferred, according to the sensory evaluation, being perceived as less acidic, less bitter, tastier, and with more intense flavor. Protective cultures can represent a practical way to reduce late blowing defects in Valtellina Casera cheese production while maintaining adherence to its PDO regulatory requirements.
This study reports the development of chitosan-based (CS) films incorporating riboflavin (RF) as a natural photosensitizer to create sustainable, light-activated antimicrobial packaging materials. The films were prepared by solvent casting, and their photochemical behavior under blue LED light (450 nm) was investigated, including RF photodegradation kinetics and structural changes in the film-forming solution analyzed by 1H NMR spectroscopy. Mechanical, thermal, optical, and barrier properties were also characterized to assess packaging suitability. Upon illumination, CS/RF films generated reactive oxygen species, particularly singlet oxygen (1O2), leading to visible color changes and significant antimicrobial activity against Pseudomonas fluorescens. Bacterial growth was reduced by up to 97% after 120 min of irradiation (0.92 J cm−2), with efficacy observed at both room temperature and 4 °C. The incorporation of RF did not alter the films’ mechanical properties, while thermal stability was preserved, optical transparency was modulated, and excellent oxygen barrier performance was maintained, although water vapor permeability remained moderate. These findings demonstrate that CS/RF films combine functionality and sustainability, offering a promising strategy for extending food shelf life through light-activated antimicrobial action. Validation under real storage conditions is recommended to confirm their potential in diverse food systems.
Paraprobiotics and postbiotics represent a valid alternative to probiotic strains for ameliorating and preserving a healthy intestinal epithelial barrier (IEB). The present study investigated the effects of surface layer proteins (S-layer) of the dairy strain Lactobacillus helveticus ATCC® 15009™ (Lb ATCC® 15009™), as paraprobiotic, on the morpho-functional modulation of IEB in comparison to live or heat-inactivated Lb ATCC® 15009™ in an in vitro co-culture of Caco-2/HT-29 70/30 cells. Live or heat-inactivated Lb ATCC® 15009™ negatively affected transepithelial electrical resistance (TEER) and paracellular permeability, and impaired the distribution of Claudin-1, a tight junction (TJ) transmembrane protein, as detected by immunofluorescence (IF). Conversely, the addition of the S-layer improved TEER and decreased permeability in physiological conditions in co-cultures with basal TEER lower than 50 ohmcm2, indicative of a more permeable physiological IEB known as leaky gut. Transmission electron microscopy (TEM) and IF analyses suggested that the S-layer induces a structural TJ rearrangement and desmosomes’ formation. S-layer also restored TEER and permeability in the presence of LPS, but not of a mixture of pro-inflammatory cytokines (TNF-α plus IFN-γ). IF analyses showed an increase in Claudin-1 staining when LPS and S-layer were co-administered with respect to LPS alone; in addition, the S-layer counteracted the reduction of alkaline phosphatase detoxification activity and the enhancement of pro-inflammatory interleukin-8 release both induced by LPS. Altogether, these data corroborate a paraprobiotic role of S-layer from Lb ATCC® 15009™ as a possible candidate for therapeutic and prophylactic uses in conditions related to gastrointestinal health and correlated with extra-intestinal disorders.
In the context of the RABOLA project, which aimed to identify operational practices that lead to the reduction of antibiotic use in dairy cattle farming, lyophilised Aloe arborescens was administered orally to cows during the dry-off and peripartum periods. In this specific paper we wanted to examine whether oral administration of Aloe arborescens, in combination with the topical application of a teat sealant could exert an effect on the microbial populations of three cow microbiomes (rumen, milk, rectum), between dry-off and peripartum. Dry-off and peripartum are critical physiological phases of the cow’s life, where both the mammary gland and the gastrointestinal tract undergo dramatic modifications, hence the relevance of evaluating the effects of dietary treatments. Thirty multiparous dairy cows were randomly allocated to three groups: Control (antibiotic treatment and internal teat sealant), Sealant (only internal teat sealant) and Aloe (internal teat sealant and Aloe arborescens homogenate administered orally). For 16S rRNA gene sequencing, rumen, rectum and milk samples were collected, not synchronously, at the most critical timepoints around dry-off and calving, considering the physiological activity of each biological site. The rumen microbiome was predominantly characterized by Bacteroidetes and Firmicutes followed by Proteobacteria, while the rectum exhibited a prevalence of Firmicutes and Bacteroidetes. The milk microbiome mainly comprised Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. Alistipes spp., Ruminococcaceae UCG-10 group, Prevotellaceae UCG-001 group, and Bacteroides spp., involved in cellulose and hemicellulose degradation, enhancement of energy metabolism, and peptide breakdown, showed increment in the rectum microbiome with Aloe supplementation. The rectum microbiome in the Aloe group exhibited a significant increase in the Firmicutes to Bacteroidetes ratio and alpha-diversity at seven days after dry-off period. Beta-diversity showed a significant separation between treatments for the rectum and milk microbiomes. Aloe supplementation seemed to enrich milk microbial composition, whereas the Sealant group showed greater diversity compared to the Control group, albeit this included an increase in microorganisms frequently associated with mastitis. Aloe arborescens administration during the dry-off period did not demonstrate any observable impact on the microbial composition of the rumen, a finding further supported by volatilome analysis. Instead, the oral Aloe supplementation at dry-off appears to significantly influence the composition of the dairy cow rectum and milk microbiomes in the following lactation.
Lactiplantibacillus plantarum (formerly known as Lactobacillus plantarum), a bacterial species isolated from a wide variety of ecological niches, plays an important role in food industries, being used as a starter culture of food fermentations and contributing to improve flavor, texture, sensorial qualities, and shelf life. It also improves the nutritional and functional properties of fermented foods through the biosynthesis of bioactive compounds and several strains exhibit probiotic features. In recent years, this bacterial species has also shown great potential for controlling plant pathogenic fungi. Shotgun proteomic approach and label free quantitative analyses were used to realize a detailed catalog of the proteins secreted by five L. plantarum strains isolated from vegetable foods or dairy products and exhibiting specific function features. In particular, these strains showed in vitro inhibitory activity against bacteria and molds. Results led to identify 602 proteins differently present in the secretome of the analyzed strains. For instance, proteins of application interest such as bacteriocins, glucansucrase, glycoside hydrolase and chitin binding proteins were differentially secreted in the five strains.The information gathered in this study is a valuable contribution to increasing knowledge in relation to one of the most important bacterial species used as probiotic, for biocontrol of plant pathogenic bacteria and fungi and in different food production worldwide.
The cheesemaking industry is increasingly interested in using adjunct cultures with potential aromatic and anticlostridial activities. In this study, 34 Lb. paracasei and 2 Lb. rhamnosus strains were isolated from a semi-hard cheese and characterized for their proteolytic, esterase, and anticlostridial activity. Moreover, the strains were inoculated in a curd-based medium and the volatile compounds in the headspace of samples were evaluated by solid-phase microextraction–GC–MS analysis. Proteolytic activity was present in 30 strains, whereas only one Lb. paracasei strain showed esterase activity. All strains inhibited Cl. sporogenes , Cl. beijerinckii , and Cl. butyricum , and 18 isolates inhibited at least one Cl. tyrobutyricum strain. Principal component analysis and clustering analysis based on the volatilome grouped strains into three groups. One of these groups was characterized by high amounts of acids and esters and clustered with control samples inoculated with commercial starter cultures, suggesting similarity in the aroma profile. Strains belonging to this group with inhibitory effects against Cl. tyrobutyricum might be exploited as autochthonous adjunct cultures for the reduction of late-blowing defects in semi-hard cheeses.
Accurate identification of the fungal community spontaneously colonizing food products, aged in natural and not controlled environments, provides information about potential mycotoxin risk associated with its consumption.Autochthonous mycobiota colonizing cheese aging in Dossena mines, was investigated and characterized by two approaches: microbial isolations and metabarcoding. Microbial isolations and metabarcoding analysis were conducted on cheese samples, obtained by four batches, produced in four different seasons of the year, aged for 90 and 180 days, by five dairy farms. The two approaches, with different taxonomical resolution power, highlighted Penicillium biforme among filamentous fungi, collected from 58 out of 68 cheeses, and Debaryomyces hansenii among yeasts, as the most abundant species (31 ÷ 65%), none representing a health risk for human cheese consumption. Shannon index showed that the richness of mycobiota increases after 180 days of maturation. Beta diversity analysis highlighted significant differences in composition of mycobiota of cheese produced by different dairy farms and aged for different durations. Weak negative growth interaction between P. biforme and Aspergillus westerdijkiae by in vitro analysis was observed leading to hypothesize that a reciprocal control is possible, also affected by natural environmental conditions, possibly disadvantageous for the last species.
Table olives, a vital category among fermented vegetables, come in treated and natural forms. Treated green olives require an alkaline treatment before brining to start fermentation. This study investigates the fermentation of unsalted Moroccan Picholine green olives using a method that includes heat shock treatment, inoculation with Lactiplantibacillus plantarum S61, and orange peel juice. The findings indicate that a heat shock at 70°C significantly reduces enterobacteria and enhances acidification, dropping pH levels from 5.0 to 3.6. In contrast, non-heat-treated olives showed only a slight pH decrease. The method also exhibited high antimicrobial activity, with substantial inhibition of E. coli, P. aeruginosa, L. monocytogenes, and S. aureus. Antifungal activity was noted, with significant inhibition of various strains. These results suggest that combining heat shock, L. plantarum S61, and orange peel juice can significantly improve the fermentation process of green olives, enhancing safety and quality.
The antibiotic administration in dairy livestock is a current widespread practice. The purpose of the study was to evaluate whether milk from antibiotic‐treated animals, following the application of the withdrawal time and fully complying with European requirements in relation to residue content, affected the development of lactic acid bacteria. Forty‐five raw milk samples were collected after the withdrawal period and analysed to verify their compliance with the European maximum limits using four commercial screening tests. Lactobacillus delbrueckii subsp. bulgaricus growth and acidifying activity were delayed from 5 to 8 h in milk from cow treated with β‐lactams and sulfonamides present in low concentration (cephalosporins < 15 μg/kg; penicillins < 8 μg/kg; sulfonamides < 10 μg/kg) and their effect persisted over time. No influences were detected in Streptococcus thermophilus and Lb. helveticus development. The use of antibiotics can hamper the starter performances, opening questions about the safety of dairy products and human health.
Enterococci are widely distributed in dairy sector. They are commensals of the gastrointestinal tract of animals, thus, via fecal contamination, could reach raw milk and dairy products. The aims of this study were: 1) to investigate the enterococcal diversity in cow feces and milk samples and 2) to evaluate the antibiotic resistance (AR) of dairy-related enterococci and their ability to transfer resistance genes. E. faecalis (59.9%), E. faecium (18.6%) and E. lactis (12.4%) were prevalent in milk, while E. faecium (84.2%) and E. hirae (15.0%) were dominant in bovine feces. RAPD-PCR highlighted a high number of Enterococcus biotypes (45 from milk and 37 from feces) and none of the milk strains exhibited genetic profiles similar to those of feces biotypes. A high percentage of enterococci isolated from milk (71%) were identified as multidrug resistant and resistance against streptomycin and tetracycline were widespread among milk strains while enterococci from feces were commonly resistant to linezolid and quinupristin/dalfopristin. Only E. faecalis strains were able to transfer horizontally the tetM gene to Lb. delbrueckii subsp. lactis. Our results indicated that Enterococcus biotypes from milk and bovine feces belong to different community and the ability of these microorganisms to transfer AR genes is strain-dependent.
Abstract Good hygienic milking practices including the disinfection of the cow teat skin before and after milking aimed at preventing the occurrence of new intramammary infections (IMI) in dairy cows. This practice is generally performed using disinfectants, and in the current context of attention to the emergence of resistances, it is of greatest interest to evaluate alternative solutions that can expand treatment options. We assessed the efficacy of a pre-dipping and a post-dipping product based on the bacteriocin-containing culture of Lactococcus cremoris strain FT27, as compared to commercial disinfectants. FT27 was selected for the bactericidal activity in vitro against food pathogens. In the present study, it also revealed a high bactericidal activity against the main mastitis pathogens, most likely related to Nisin A production, according to genomic and proteomic analysis. The lactococcus-based preparations were applied in two commercial dairy farms in Northern Italy. Overall, 298 dairy cows were enrolled, 141 in the treated group (TR), and 157 in the control group (CTR). The cows were sampled at quarter level every two weeks for 3 months. During the trial, all cows showed a good health status. The hygiene level for udder, flanks and legs was generally good (on average < 3 score); the udder hygiene was significantly worse (P < 0.01) in the CTR group. The teat apex hyperkeratosis was overall low (on average < 2 score). We recorded no significant differences between the two experimental groups in the Somatic Cell Count (SCC) values and the bacteriological results. The overall frequency of new IMI was low, ranging 0.6 − 0.5% for S. aureus in the TR or CTR group respectively, to 2.6–4.4% for NASM. Regarding Str. spp., the new IMI accounted for 1.7% or 1.9% in the TR or CTR group, respectively. Notably, the incidence of S. aureus new IMI did not increase during the study, even though neither of the two herds segregated the positive cows. The non-inferiority test showed that the Lactococcus-based pre- and post-dipping products had an efficacy comparable to proven commercial disinfectants in maintaining udder health and preventing new IMI, thus representing a possible alternative to current teat dip products.
The present study reports on the valorisation of starch waste biomass to produce dual-active cryogels and hydrogels able to adsorb water and deliver antimicrobial substances for fresh food packaging applications. Starch hydrogels were prepared by oxidation with sodium metaperiodate in water and mild conditions, while cryogels were obtained by freeze-drying process. To explore the role of starch composition on the final properties of materials, two starches differing in amylose/amylopectin ratio, were evaluated. The prepared materials were microstructurally and morphologically characterized by FTIR and NMR spectroscopy (1D, 2D, and DOSY experiments), and SEM microscopy. To provide the materials with active properties, they were loaded with antimicrobial molecules by absorption, or by crosslinking via Schiff-base reaction. All materials demonstrated high water absorption capacity and ability to deliver volatile molecules, including diacetyl and complex mixtures like mint essential oil. The release profiles of the adsorbed molecules were determined through quantitative NMR spectroscopy over time. The antibacterial activity was successfully demonstrated against Gram-positive bacterial strains for unloaded cryogels and hydrogels, and after loading with diacetyl and essential oil. The developed materials can be regarded as part of active pads for food packaging applications capable to control moisture inside the package and inhibit microbial contamination.