Alginate is a natural biopolymer that forms, in the presence of divalent cations, ionic-bound gels typifying a large class of biological gels stabilized by non-covalent cross-links, and displaying a consistent restructuring kinetics. We investigate the kinetics of formation and aging of alginate gels by slow permeation of a curing CaCl₂ agent by means of photon correlation imaging, a novel optical technique that allows obtaining the microscopic dynamics of the sample, while retaining at the same time the spatial resolution of imaging techniques. Specifically, the gelling kinetics displays a peculiar non-diffusive behavior, and the subsequent restructuring of the gel structure shares several features in common with the aging of colloidal gels, in particular for what concerns the occurrence of heterogeneous dynamics effects. A comparative analysis of the gel macroscopic mechanical properties at different aging stages further highlights distinctive effects arising from the non-permanent nature of the bonds.

BACKGROUND: Ultrasound‐assisted extraction of the intermediate product from the mechanical expression of hemp (Cannabis sativa L.) seed oil was investigated to improve the overall expression yield without compromising oil quality. Complementary ultrasound technology was used as an out‐of‐line treatment carried out at 20 kHz frequency and optimized with respect to amplitude (80 and 152 μm), sonication time (2, 10, 20 min) and to the hemp paste properties, in particular its particle size and hydration, which drive the compressibility of the press cake.RESULTS: Under the conditions evaluated, the optimal ultrasound treatment was found to be the one applied on the hydrated press cake for 2 min at 152 μm, which resulted in an oil yield of 13.4%, with an increase in extraction efficiency equal to 73% with respect to the control (untreated press cake). Sonication had a positive effect on the press cake texture and on the extracted oil antioxidant activity. Soaked samples treated for 2 min at 152 μm yielded the lowest hardness. Oil recovered from soaked samples treated at 80 μm and 152 μm ultrasound for 2 min had the highest antioxidant capacity.CONCLUSIONS: The technological results gathered in the present investigation are preliminary to the design and engineering of scaled‐up equipment that combines the mechanical screw expression and the in‐line ultrasound unit. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

In a context where whey proteins currently dominate the protein sports beverage sector and pea proteins are usually commercialized as protein sources, this study proposes using sunflower press-cake, which contains approximately 44% protein, as an alternative and sustainable protein source. After the extraction from the press-cake, sunflower proteins were dispersed in an aqueous medium with varying xanthan gum concentrations (0.2%, 0.4% and 0.6% w/v) to simulate protein-rich sports beverages. Their performance was compared to that of whey and pea proteins, each at a 10% concentration. To enhance protein dispersibility and align with the trends of alkaline beverages, a K–P buffer at pH 9 was used as the dispersion medium, and 0.2% caffeine was included for cognitive benefits. Pasteurized dispersions were tested for rheological behavior and physical stability at 4 °C. Sunflower proteins, with a total polyphenolic content (TPC) of 35.2 mg_GAE g_DB ⁻¹, outperformed whey (0.8 mg_GAE g_DB ⁻¹) and pea (2.8 mg_GAE g_DB ⁻¹) proteins. Sunflower dispersions exhibited a significantly lower volatile profile than those enriched with pea or whey proteins, reducing the need for odor-masking agents. Additionally, sunflower dispersions had a lower flow index than whey or pea dispersions, indicating easier processing. Despite the promising flow behaviour and optimal physical stability (stability index < 1.0), in vitro bioaccessibility analysis revealed a similar percentage of protein bioaccessibility between pea and whey dispersions, while sunflower ones had the lowest percentage. TPC bioaccessibility followed a similar trend. These findings highlight the feasibility of incorporating sunflower proteins into sports beverages, broadening options for formulators and promoting sustainability by repurposing agricultural by-products and adopting plant-based proteins.

Ready-to-eat salads are very perishable with quality losses within 6–7 days, and the extension of their shelf life is still a challenge. In this work, an atmospheric pressure plasma jet (APPJ) was applied for the surface decontamination of fresh-cut lettuce baby leaves. The APPJ antimicrobial efficiency on the natural microbiota and its impact on some physicochemical attributes of lettuce were evaluated as a function of the treatment duration (0–30 s). Then, the influence of plasma treatment on the salad shelf life was studied, following the growth of aerobic mesophilic bacteria in both untreated and plasma-treated samples during 9 days of storage at 4 °C, together with the plasma-induced changes in physicochemical parameters of lettuce leaves. The APPJ induced a fast (15 s) microbial decontamination (1.3 log₁₀ CFU/g) of the salad surface. Exposure time and salad-plasma plume distance were the parameters that substantially affected the microbial inactivation. APPJ treatment retarded bacterial growth during the refrigerated storage, as plasma-treated samples were noticeably less contaminated than the non-treated ones in the first 3–4 days. No significant effect were observed on electrolyte leakage, pH, and dry matter content in both the set up phase and the shelf life study.