High pressure and thermal processing on the quality of zucchini slices

AbstractIn response to the market demand for low processed vegetables, high-pressure treatments (400,600 MPa; 1,5 min) were applied on zucchini slices and compared to a traditional blanching treatment. Histological observations, texture and color analysis, pectinmethylesterase (PME) and antioxidant (DPPH) activities were measured and compared to untreated samples. The histological observations revealed that the longer high-pressure treatments (5 min) led to more extended cell lysis and dehydration than the shorter ones (1 min) and blanching. High-pressure treatments resulted less effective than blanching on PME inactivation, with the best results obtained at 400 MPa for 1 min. Comparable texture parameters were observed for high-pressured and blanched samples. The negative correlation found between PME activity and the texture parameter 'distance of the first peak force' revealed an effect of PME on the texture recovery after treatments. High pressure led to a general browning of zucchini parenchyma and to DPPH drop. The correlations found between DPPH and color suggest the common nature of the phenomena. The influence of pressure and time on the studied parameters was revealed by two-way ANOVA. Principal component analysis clustered together the four high-pressure-treated samples, being clearly divided by blanched and untreated ones

Oxidative Status of Ultra-Processed Foods in the Western Diet

Ultra-processed foods (UPFs) have gained substantial attention in the scientific community due to their surging consumption and potential health repercussions. In addition to their well-established poor nutritional profile, UPFs have been implicated in containing various dietary oxidized sterols (DOxSs). These DOxSs are associated with a spectrum of chronic diseases, including cardiometabolic conditions, cancer, diabetes, Parkinson’s, and Alzheimer’s disease. In this study, we present a comprehensive database documenting the presence of DOxSs and other dietary metabolites in >60 UPFs commonly consumed as part of the Western diet. Significant differences were found in DOxS and phytosterol content between ready-to-eat (RTE) and fast foods (FFs). Biomarker analysis revealed that DOxS accumulation, particularly 25-OH and triol, can potentially discriminate between RTEs and FFs. This work underscores the potential utility of dietary biomarkers in early disease detection and prevention. However, an essential next step is conducting exposure assessments to better comprehend the levels of DOxS exposure and their association with chronic diseases

Impact of thermal and high pressure processing on quality parameters of beetroot (Beta vulgaris L.)

In this work, high-hydrostatic pressure (HHP) treatments of 650 MPa at different processing times (3, 7, 15 and 30 min) were applied on beetroot slices (var. Red cloud) as an alternative to blanching pretreatment (90 °C for 7 min). Polyphenol oxidase (PPO) and peroxidase (POD) activity, physical (texture and color) and nutritional (betanins retention, total phenolic content, antioxidant capacity and ascorbic acid) parameters were evaluated. Differently from blanching, HHP led only to partial inactivation of PPO (10e25%) and POD (25%) at each tested time. Total phenol content and FRAP value were found to be statistically similar (p > 0.05) in HHP-treated and blanched beetroot. An increase of betanins content was observed in HHP-treated samples, resulting in 6-fold higher content in comparison to the raw. However, the higher the time-exposure to high pressure, the higher pigments degradation, as similarly observed for ascorbic acid. Finally, texture properties such as hardness and chewiness were better retained in HHP samples than in thermally treated ones, showing an increase according to the time of pressure exposure. Overall, the HHP processes improved the nutritional quality of the products, as revealed from the principal component analysis

Extrusion processing characteristics of quinoa (Chenopodium quinoa Willd.) var. Cherry Vanilla

Extrusion processing characteristics of Cherry Vanilla quinoa flour (Chenopodium quinoa Willd) were investigated using a three factor response surface design to assess the impact of feed moisture, temperature, and screw speed on the physicochemical properties of quinoa extrudates. Specific mechanical energy (SME) required to extrude this quinoa variety was higher (250–500 kJ/kg) than previously reported for quinoa. The following characteristics of the extrudates were observed: expansion ratio (1.17–1.55 g/cm3), unit density (0.45–1.02 g/cm3), water absorption index (WAI) (2.33–3.05 g/g), and water solubility index (WSI) (14.5–15.87%). This quinoa flour had relatively low direct expansion compared to cereal grains such as corn or wheat, suggesting that it is not well suited for the making of direct expanded products. The study further suggests that there is a need to understand the processing characteristics of new quinoa varieties for cultivation. Understanding extrusion and other quality traits in advance will help to select the appropriate varieties that would allow food processors to meet consumer needs. •A predictive model for extrusion of a new breeding line of quinoa is disclosed.•Large increase in quinoa darkness were found to occur with high moisture.•Saponin and phenolic reduction through temperature effects of extrusion are explored.•Conclusions are drawn on how various extruded quinoa products can be produced

Improved Physicochemical and Structural Properties of Blueberries by High Hydrostatic Pressure Processing

The use of high pressure on fruits and vegetables is today widely studied as an alternative to the traditional thermal preservation techniques, with the aim of better preserving nutritional and organoleptic properties. The use of high hydrostatic pressures (400–600 MPa; 1–5 min; room temperature) was tested on the physicochemical and structural properties of blueberries, in comparison to raw and blanched samples. High hydrostatic pressures led to higher tissue damages than blanching, related to the intensity of the treatment. The cellular damages resulted in leakage of intracellular components, such as bioactive molecules and enzymes. As a consequence, among the high pressure treatments, the resulting antioxidant activity was higher for samples treated for longer times (5 min). Pectinmethyl esterase (PME), deactivated by blanching, but strongly barotolerant, was more active in blueberries treated with the more intense high pressure conditions. Blueberry texture was better retained after high pressure than blanching, probably because of the PME effect. Blueberry color shifted towards purple tones after all of the treatments, which was more affected by blanching. Principal component analysis revealed the mild impact of high pressure treatments on the organoleptic properties of blueberries