Vacuum-steam pulsed blanching (VSPB): An emerging blanching technology for beetroot

Mechanistic understanding of the improved drying characteristics and quality attributes of lily (Lilium lancifolium Thunb.) by modified microstructure after pulsed electric field (PEF) pretreatment

The effects of the non-thermal (pulsed electric field, PEF) and thermal pretreatment (vacuum steam pulsed blanching, VSPB) on the drying kinetics, quality attributes, and multi-dimensional microstructure of lily scales were investigated. The results indicate that both PEF and VSPB pretreatments improved the drying rate compared to untreated lily scales. Specifically, PEF pretreatment reduced the drying time by 29.58 % - 43.60 %, while VSPB achieved a 46.91 % reduction in drying time. PEF treatment facilitated the enhanced leaching of phenols and flavonoids compared to VSPB treated samples, thereby increasing antioxidant activity. The rehydration ratio of the dried lilies was improved with PEF and VSPB treatment, which closely related to the microstructure. Weibull distribution and Page model demonstrated excellent fit for the drying and rehydration kinetics of lily scales, respectively (R2 > 0.993). The analysis of multi-dimensional microstructure and ultrastructure confirmed the variations in moisture migration and phytochemical contents among different treatments. Consequently, this study offers insights into the technological support for the potential of non-thermal pretreatment in fruits and vegetables.

Investigating the effect of red beetroot powder concentration and processing time on the bioactive compounds composition and antioxidant capacity of beetroot dark chocolate

BACKGROUND

The development of functional foods is receiving increased recognition as a result of the general interest in healthy diets as part of a healthier lifestyle. This project sought to incorporate red beetroot in dark chocolate and investigate the effect of beetroot powder concentration and processing time on the chocolates' bioactive compound composition, antioxidant capacity, and sugar content.

RESULTS

The results showed the presence of bioactive compounds such as betalains and vitamin C in the red beetroot with relatively high antioxidant capacity. The addition of beetroot powder to dark chocolate increased the majority of the bioactive compounds (e.g. catechin, epicatechin, betalains, vitamin C) while at the same time increasing the antioxidant capacity. It also resulted in a decrease in sugar content. Except for vitamin C, processing for more than 12 h had an increasing effect on the majority of the bioactive compounds. Beetroot powder incorporation at a maximum of 30% and processing for 24 h was regarded as optimal.

CONCLUSION

Overall, the present study suggests that red beetroot powder could be added to dark chocolates and processed for more than 12 h to increase the bioactive compounds and overall antioxidant capacity. This research would help to diversify beetroot utilization, reduce post-harvest losses, and improve the overall health-promoting properties of dark chocolate for improved consumer well-being. © 2023 Society of Chemical Industry.

Vacuum-steam pulsed blanching: An emerging method to enhance texture softening, drying behavior and physicochemical properties of Cornus officinalis

Vacuum steam pulsed blanching (VSPB) was employed as a novel blanching technology on Cornus officinalis to soften the tissue for subsequent coring and dehydration. The current work aims to explore its effect on mass transfer behavior, PPO inactivation, drying characteristics, physicochemical properties, antioxidant capacity, and microstructure of C. officinalis. Results showed that VSPB increased water loss, decreased solid gain, and increased weight reduction with increased blanching cycles. Besides, VSPB significantly changed physical properties and extensively reduced drying time which was attributed to the cell wall components dissolving and cell turgor pressure decreasing, also verified by observing microstructure alteration. PPO was completely denatured after blanching in 6 cycles, but phenolic compounds were still diffused or degraded. Notably, the content of flavonoids and antioxidant capacity significantly increased compared to fresh samples probably due to increased extractability caused by the disrupting cell structure. Besides, the carotenoids and ascorbic acid could be well preserved.

Effect of lacto-fermentation and freeze-drying on the quality of beetroot evaluated using machine vision and sensory analysis

This study was aimed at evaluating the effect of freeze-drying and lacto-fermentation on the texture parameters of images and sensory attributes of beetroots. The samples were imaged using a flatbed scanner, and textures from images converted to color channels L, a, b, R, G, B, X, Y, Z were computed. The discrimination of raw and processed beetroots was performed using models based on textures selected for each color channel. The sensory quality of processed samples was determined using the attributes related to smell, color, texture and taste. The highest discrimination accuracy of 97.25% was obtained for the model built for color channel b. The accuracies for other channels were equal to 96.25% for channel a, 95.25% for channel R, 95% for channel Y, 94.75% for channel B, 94.5% for channel X, 94% for channel L, 92.5% for channel G, 88.25% for channel Z. In the case of some models, the raw and lacto-fermented beetroots were discriminated with 100% correctness. The freeze-dried and freeze-dried lacto-fermented samples were also the most similar in terms of sensory attributes, such as off-odor, attractiveness color, beetroot color, crunchiness, hardness, bitter taste, overall quality. The results indicated that the image parameters and sensory attributes may be related.