Continuous-Flow High-Pressure Homogenization of Blueberry Juice Enhances Anthocyanin and Ascorbic Acid Stability during Cold Storage.

Blueberries (Vaccinium section Cyanococcus) have a wealth of bioactive compounds, including anthocyanins and other antioxidants, that offer significant health benefits. Preserving these compounds and maintaining the sensory and nutritional qualities of blueberry products such as juice during cold market storage is critical to meet consumer expectations for nutritious, safe, and minimally processed food. In this study, we compared the effects of two preservation processing techniques, high-temperature short-time (HTST) and continuous flow high-pressure homogenization (CFHPH), on blueberry juice quality during storage at 4 °C. Our findings revealed that inlet temperature (Tin) of CFHPH processing at 4 °C favored anthocyanin retention, whereas Tin at 22 °C favored ascorbic acid retention. After 45 days of storage, CFHPH (300 MPa, 1.5 L/min, 4 °C) juice retained up to 54% more anthocyanins compared to control at 0 day. In contrast, HTST treatment (95 °C, 15 s) initially increased anthocyanin concentrations but led to their subsequent degradation over time, while also significantly degrading ascorbic acid. Furthermore, CFHPH (300 MPa, 4 °C) juice had significantly lower polyphenol oxidase activity (>80% less than control), contributing to the overall quality of the juice. This innovative processing technique has the potential to improve commercial blueberry juice, and help meet the rising demand for healthy and appealing food choices.

A comparison of fatty acid and sensory profiles of raw and roasted pecan cultivars.

Five fatty acids comprise the bulk of the lipid content in pecans: palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Understanding the profiles of these fatty acids and how they relate to sensory characteristics may offer an explanation for flavor and flavor defects that may exist in certain cultivars of pecans. The objective of this study was to examine and compare fatty acid profiles of three cultivars of pecans (Major, Lakota, and Chetopa), over two crop years, under raw and roasted preparation methods, and understand the fatty acids association with sensory attributes. Percentages of palmitic, stearic, oleic, linoleic, and linolenic acids to total fatty acid content were determined using gas chromatography, and sensory profiles were generated using descriptive sensory analysis. Similar trends were seen across samples, with oleic acid comprising the majority of the total fatty acids and linolenic acid comprising the smallest percentage. There were significant differences in fatty acid content among cultivars and between pecans in the first and second crop year. Few associations were found between the fatty acids and sensory attributes, which suggest that combinations of the fatty acids contribute to certain pleasant or undesirable flavor attributes in the pecans. Subtle differences in fatty acid composition may lead to variation in flavor and flavor intensity or draw attention to or from certain attributes during consumption. Differences in crop year indicated that fatty acid content and therefore flavor are variable year to year. PRACTICAL APPLICATION: This study will help understand how fatty acid content of pecans varies from year to year. This should be taken into account when manufacturing products with pecans as the nutritional content of the product may change as the result.

Interactions of Carvacrol, Caprylic Acid, Habituation, and Mild Heat for Pressure-Based Inactivation of O157 and Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Acidic Environment.

The current study investigated synergism of elevated hydrostatic pressure, habituation, mild heat, and antimicrobials for inactivation of O157 and non-O157 serogroups of Shiga toxin-producing Escherichia coli. Various times at a pressure intensity level of 450 MPa were investigated at 4 and 45 °C with and without carvacrol, and caprylic acid before and after three-day aerobic habituation in blueberry juice. Experiments were conducted in three biologically independent repetitions each consist of two replications and were statistically analyzed as a randomized complete block design study using ANOVA followed by Tukey- and Dunnett's-adjusted mean separations. Under the condition of this experiment, habituation of the microbial pathogen played an influential (p < 0.05) role on inactivation rate of the pathogen. As an example, O157 and non-O157 serogroups were reduced (p < 0.05) by 1.4 and 1.6 Log CFU/mL after a 450 MPa treatment at 4 °C for seven min, respectively, before habituation. The corresponding log reductions (p < 0.05) after three-day aerobic habituation were: 2.6, and 3.3, respectively at 4 °C. Carvacrol and caprylic acid addition both augmented the pressure-based decontamination efficacy. As an example, Escherichia coli O157 were reduced (p < 0.05) by 2.6 and 4.2 log CFU/mL after a seven-min treatment at 450 MPa without, and with presence of 0.5% carvacrol, respectively, at 4 °C.