High pressure processing at different hydration levels as a tool to enhance rice bran stability and techno-functionality

High-pressure processing (HPP) enhances food safety and shelf life by inactivating microorganisms and preserving food quality, yet its effectiveness in low-humidity environments has not been evaluated. This study investigated the effects of HPP at 500 MPa for 15 min across varying hydration levels (15, 30, 60, 77 %) on rice bran (RB), aiming to identify microbial effectiveness, besides techno-functional and physicochemical properties. HPP effectively reduced mesophilic bacteria, molds and yeast of RB at > 15 % hydration level, achieving reductions of up to 4 logarithmic cycles in the latter, nearing the detection limit of the method. However, it did not significantly impact spore inactivation. HPP treatment of ≥ 30 % hydrated RB induced particles aggregation and a honeycomb formation. The interaction between hydration and HPP treatment significantly affected the distribution of total dietary fibers, with an increase in soluble dietary fiber from 8.73 g/100 g to 11.03 g/100 g after HPP treatment at 15 % hydration level. Protein solubility was enhanced by hydration (15, 30 and 60 %), and peroxide values decreased after HPP treatment at low hydration (≤30 %) but increased when applied to high hydrated (>30 %) RB. Emulsifying activity decreased upon HPP treatment of highly hydrated RB (≥60 %), but more stable emulsions were achieved after HPP, regardless of the hydration level. Therefore, this study highlights the potential of HPP as a sustainable approach to enhance the utilization of rice bran in food applications, addressing existing knowledge gaps regarding its processing under different moisture conditions.

Effect of Ultrasound and High Hydrostatic Pressure Processing on Quality and Bioactive Compounds during the Shelf Life of a Broccoli and Carrot By-Products Beverage

Vegetable beverages are a convenient strategy to enhance the consumption of horticultural commodities, with the possibility of being fortified with plant by-products to increase functional quality. The main objective was to develop a new veggie beverage from broccoli stalks and carrot by-products seasoned with natural antioxidants and antimicrobial ingredients. Pasteurization, Ultrasound (US), and High Hydrostatic Pressure (HHP) and their combinations were used as processing treatments, while no treatment was used as a control (CTRL). A shelf-life study of 28 days at 4 °C was assayed. Microbial load, antioxidant capacity, and bioactive compounds were periodically measured. Non-thermal treatments have successfully preserved antioxidants (~6 mg/L ΣCarotenoids) and sulfur compounds (~1.25 g/L ΣGlucosinolates and ~5.5 mg/L sulforaphane) throughout the refrigerated storage, with a longer shelf life compared to a pasteurized beverage. Total vial count was reduced by 1.5-2 log CFU/mL at day 0 and by 6 log CFU/mL at the end of the storage in HHP treatments. Thus, the product developed in this study could help increase the daily intake of glucosinolates and carotenoids. These beverages can be a good strategy to revitalize broccoli and carrot by-products with high nutritional potential while maintaining a pleasant sensory perception for the final consumer.

Microbial decontamination assisted by ultrasound-based processing technologies in food and model systems: A review

Ultrasound (US) technology is recognized as one of the emerging technologies that arise from the current trends for improving nutritional and organoleptic properties while providing food safety. However, when applying the US alone, higher power and longer treatment times than conventional thermal treatments are needed to achieve a comparable level of microbial inactivation. This results in risks, damaging food products' composition, structure, or sensory properties, and can lead to higher processing costs. Therefore, the US has often been investigated in combination with other approaches, like heating at mild temperatures and/or treatments at elevated pressure, use of antimicrobial substances, or other emerging technologies (e.g., high-pressure processing, pulsed electric fields, nonthermal plasma, or microwaves). A combination of US with different approaches has been reported to be less energy and time consuming. This manuscript aims to provide a broad review of the microbial inactivation efficacy of US technology in different food matrices and model systems. In particular, emphasis is given to the US in combination with the two most industrially viable physical processes, that is, heating at mild temperatures and/or treatments at elevated pressure, resulting in techniques known as thermosonication, manosonication, and manothermosonication. The available literature is reviewed, and critically discussed, and potential research gaps are identified. Additionally, discussions on the US's inactivation mechanisms and lethal effects are included. Finally, mathematical modeling approaches of microbial inactivation kinetics due to US-based processing technologies are also outlined. Overall, this review focuses only on the uses of the US and its combinations with other processes relevant to microbial food decontamination.

Ultrasonication Effects on Quality of Tea-Based Beverages

Tea is the most popular consumed drink after water. Teas and tea-based beverages have grown in popularity due to bioactive compounds. Tea-based beverages have started to take their place in the market. Extraction is a crucial step for the production of functional tea-based beverages. Compared to conventional methods, ultrasound is attractive due to its lower energy requirements, and shorter extraction time. This review aimed to discuss recent marketing aspects of tea-based beverages as well as the potential and challenges of a novel infusion technique. This review describes the health benefits and technological aspects of tea-based beverages in relation to how to best solve nutritional and microbial concerns. Current and future challenges and opportunities of the novel infusion technique and its scaling-up for the extraction of bioactive compounds are also covered in the present review.

Relationship between the turbidity difference and the grade of green tea under Ca2+ acceleration: A preliminary study

The grade of green tea indicates its intrinsic quality and guides consumers when purchasing. Simple, accessible, and on-site determination of green tea grades is essential for consumers and regulators. In this study, we assumed that the turbidity difference in green tea might indicate its grade, and our results confirmed this hypothesis. The turbidity difference was measured in green tea infusions before and after the Ca2+ acceleration. For the same kind of green tea, it was found that higher grades of green tea had larger turbidity differences. Effects of brewing temperature, brewing time, Ca2+ concentration, and Ca2+ treatment time on the turbidity of green tea infusions were analyzed, and their optimal values were obtained. This study demonstrates that applying the turbidity difference and Ca2+ acceleration could be an accessible method for the on-site determination of green tea grades.