Effect of UV-C radiation treatment on microbial load and antioxidant capacity in hot pepper, fennel and coriander

A comprehensive review on ultraviolet disinfection of spices and culinary seeds and its effect on quality

Spices and culinary seeds, valued for their flavor and aroma, pose unique challenges for disinfection, as heat treatments are often unsuitable. Their raw consumption increases the risk of contamination, particularly with Salmonella spp. Thermal treatments are widely used for food disinfection due to their effectiveness in inactivating bacteria. However, these methods often degrade the nutritional and sensory qualities of food. Ultraviolet (UV) light, however, is a promising nonthermal technique that balances microbial inactivation and food quality preservation. This review employed a systematic approach to evaluate the effects of UV treatments, both alone and in combination with other techniques, on the microbiological safety and chemical composition of spices and culinary seeds. UV treatments have been shown to effectively inactivate bacteria, molds, and mycotoxins without triggering the same chemical reactions that reduce the quality of plant-based foods. Some studies have even suggested improvements in nutritional parameters following UV exposure, such as the increase of antioxidant activity or total phenolic content. However, inconsistencies in study quality limit the strength of current conclusions, and further research is needed. Critical areas for future investigation include scaling UV reactors, combining treatments, exploring UV-LED technology, conducting sensory analyses, and studying the inactivation of bacterial spores and mycotoxins.

Quality characteristics of goat milk powder produced by freeze drying followed by UV-C radiation sterilization

Goat milk was directly freeze-dried into milk powder after freezing and then sterilized using UV-C radiation to produce low-dose, medium-dose and high-dose UV-C radiation sterilized freeze-dried goat milk powder (LGP, MGP and HGP). UV-C sterilization effectively reduced the total bacteria count and coliform bacteria in the goat milk powder while preserving the active proteins, and maintaining the color unchanged. Additionally, LGP, MGP, and HGP all exhibited a moisture content below 5 g/100 g and water activity below 0.5. Upon reconstitution, the milk powder formed uniform and stable emulsion. During accelerated storage tests, the increased Aw did not compromise the microbial quality of milk powder, and there were no significant changes in active proteins as confirmed via SDS-PAGE results. Furthermore, the color parameters (a*, b* and ΔE) showed a strong correlation with hydroxymethyl furfural levels.

Physicochemical, sensory and microbiological characteristics of coriander seed powder yogurt

Yogurt is a fermented food obtained by the bacterial fermentation of milk. In the present work, the effect of different concentrations (1, 3 and 5% w/w) of coriander (Coriandrum sativum) seed powder on physicochemical, sensory characteristics and viability of Bifidobacterium bifidum and Lactobacillus acidophilus of probiotic yogurt were investigated at 4 °C for 21 days. Laboratory-made yogurts were obtained by inoculating milk with yogurt bacteria (mixed culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) and two probiotic cultures (Lactobacillus acidophilus and Bifidobacterium bifidum). According to the results, the viability of B. bifidum and L. acidophilus increased in synbiotic stirred yogurts with 5% CSP (coriander seed powder) up to 9.15 ± 0.09 log CFU/g at 11 days of the storage period, whereas probiotic bacteria count decreased to 9.02 ± 0.01 by the end. Therefore, our results confirmed that the addition of probiotics and CSP powder improved the physicochemical and sensory characteristics of stirred yogurt and exerted a beneficial effect on probiotic bacteria.

Antioxidant Activity of Plant-Derived Colorants for Potential Cosmetic Application

Application of plant-derived colorants in products, i.e., cosmetics or food, apart from imparting the desired color without harming the environment, may provide other benefits. Valuable ingredients in cosmetic formulations include antioxidants showing an advantageous effect on the skin by neutralizing free radicals that accelerate the aging process and cause skin defects. Antioxidant activity can be determined by chemical-based methods. The aim of this study was to determine the antioxidant activity of plant-derived colorants (purple and red colorant) by two methods: CUPRAC and DPPH free-radical scavenging activity. Antioxidant activity evaluation using both methods for colorants samples was also performed after 5, 15, 30, and 60 min of exposure to UVC irradiation. The results obtained by CUPRAC method were for purple and red colorant unexposed samples as follows: 6.87 ± 0.09 and 4.48 ± 0.14 mg/100 mg colorant expressed as caffeic acid equivalent, respectively. UVC treatment did not affect the results of the antioxidant activity for red colorant and for the purple one only a slight influence was observed. DPPH free-radical scavenging activity for unexposed samples was 70.06 ± 7.74% DPPH/100 mg colorant for the red colorant and 96.11 ± 3.80% DPPH/100 mg colorant for the purple one.