Recovering high value-added anthocyanins from blueberry pomace with ultrasound-assisted extraction

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Food waste blueberry pomace offers a high potential to recover anthocyanins.

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Ultrasonic-assisted extraction of anthocyanins was optimized by Box-Behnken design.

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The optimal parameters of ultrasonic treatment were 40 °C and 400 W for 40 min.

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Highly purified blueberry anthocyanins were obtained after SCX cation exchange.

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Malvidin was the main anthocyanins in the purified fractions from blueberry pomace.

Food waste is a potential source to replace fresh materials for obtaining functional ingredients. Blueberry pomace contains considerable amounts of anthocyanins. In this study, we investigated ultrasonic-assisted extraction (UAE) of anthocyanins from blueberry pomace. We used a Box-Behnken design (BBD) to screen and optimize the important factors influencing yield. The optimum extraction conditions were a temperature of 40 °C, an ultrasonic power of 400 W and an extraction time of 40 min. The optimum yield was 108.23 mg/100 g DW. In addition, we used a cation column to separate anthocyanins, and optimized the chromatographic conditions of HPLC to analyze and identify the main anthocyanins. Thirteen anthocyanins were found in blueberry pomace, of which Malvidin-3-Galactoside (22.65 %) was the highest. These findings provide a theoretical basis and optimized process parameters for the recovery of high value-added anthocyanins from blueberry pomace with ultrasound-assisted extraction, thus facilitating the comprehensive utilization of blueberry pomace.

Growth Inhibition and Alternation of Virulence Genes of Salmonella on Produce Products Treated with Polyphenolic Extracts from Berry Pomace

ABSTRACT

Organic farming, including integrated crop-livestock farms and backyard farming, is gaining popularity in the United States, and products from these farms are commonly sold at farmers' markets, local stores, and roadside stalls. Because organic farms avoid using antibiotics and chemicals and because they use composted animal waste and nonprofessional harvesting and packaging methods, their products have an increased risk of cross-contamination with zoonotic pathogens. This study sets out to evaluate the efficiency of new postharvest disinfection processes using natural berry pomace extracts (BPEs) as a means to reduce the bacterial load found in two common leafy greens, spinach and celery. Spinach and celery were inoculated with a fixed bacterial load of Salmonella Typhimurium and later were soaked in BPE-supplemented water (wBPE) for increasing periods of time, at two different temperatures (24 and 4°C). The remaining live bacteria were quantified (log CFU per leaf), and numbers were compared with those on vegetables soaked in water alone. The relative expression of virulence genes (hilA1/C1/D1, invA1/C1/E1/F1) of wBPE-treated Salmonella Typhimurium was determined. For spinach, there was a significant (P < 0.05) reduction of Salmonella Typhimurium: 0.2 to 1.2 log CFU/mL and 0.5 to 5 log CFU/mL at 24 and 4°C, respectively. For celery, there was also a significant (P < 0.05) reduction of Salmonella Typhimurium at either 24 or 4°C. The changes in relative expression of virulence genes of Salmonella Typhimurium isolated from spinach and celery varied depending on the treatment conditions but showed a significant down-regulation of inv genes when treated at 24°C for 1,440 min (P < 0.05). After seven uses, the total polyphenolic compounds in wBPE remained at an effective concentration. This research suggests that soaking these vegetables with BPE-containing water at lower temperatures can still reduce the Salmonella Typhimurium load enough to minimize the risk of infection and alter virulence properties.

HIGHLIGHTS

Development and characterization of cassava starch films incorporated with blueberry pomace

This work is focused on the development of renewable and biodegradable films by the valorisation of wastes from food processing industries, with the aim of contributing to the development of more sustainable films. In this context, different contents of blueberry pomace (BP) were incorporated into cassava starch (CS) film forming solutions and the functional properties of the films prepared by solution casting were investigated, specifically, thermal, optical and physicochemical properties. BP-incorporated films showed good barrier properties against light, indicating their beneficial effect to prevent food deterioration caused by UV radiation when these films are used for food packaging applications. These results were related to the presence of aromatic compounds in BP, which can absorb light at wavelengths below 300nm. Furthermore, all films maintained their structural integrity after immersion in water (24h) and the maximum swelling displayed was lower than 300%. Additionally, the release of active compounds from BP into food simulants (after 10days) showed higher migration into the acetic acid medium in comparison with the ethanol medium. Therefore, the incorporation of BP into CS film forming solution resulted in the improvement of film performance, suggesting the potential application of these films as active packaging.