Effect of dehydration and pulsed light treatment on decontamination of minced onions: Microbial safety and physicochemical properties

Microbial contamination of dehydrated onion products is a challenge to the industry. The study focused on opting for a suitable drying condition for minced onion and exploring the decontamination efficacy of pulsed light (PL) treatment conditions for the dehydrated product. The minced onions were hot air dried at 55-75°C for 280 min. The drying condition selected was 195 min at 75°C with a final water activity of 0.5 and moisture content of 7% (wet basis [w.b.]). The weight losses, browning indexes (BI), shrinkage volumes (%), and thiosulfinate content were considered. The dehydrated product was exposed to PL treatment corresponding to an effective fluence range of 0.007-0.731 J/cm2. A fluence of 0.444 J/cm2 (1.8 kV for 150 s) achieved 5.00, 3.14, 2.96, and 2.98 log reduction in total plate count, yeast and mold count, Bacillus cereus 10876, and Escherichia coli ATCC 43888, respectively. The PL-treated sample (0.444 J/cm2) produced a microbially safe product with no significant difference in the moisture contents (%w.b.) and water activity (aw) from the untreated dehydrated sample. Further, a 30.9% increase in the BI and a 4.25% depletion in thiosulfinate content were observed after PL treatment. An optimum drying combination (75°C for 195 min) of minced onion followed by decontamination using pulsed light treatment at 0.444 J/cm2 fluence satisfies the microbial safety and quality. PRACTICAL APPLICATION: Dehydrated minced onion can be used for dishes requiring low water content and short cooking time. It is helpful during shortages, high price fluctuations, and famines.

Effect of Oat Fiber Preparations with Different Contents of β-Glucan on the Formation of Acrylamide in Dietary Bread (Rusks)

In the literature, there are few reports indicating hydrocolloids as a factor capable of reducing the amount of acrylamide formed in food. Therefore, the aim of the study was to examine the ability of soluble oat fiber to reduce the amount of acrylamide formed in the process of obtaining rusks. The effect of the concentration of β-glucans in oat fiber preparations at 20% and 30% and the amount of preparations used at 10%, 15%, and 20% was investigated. On the basis of the obtained test results, it was shown that the most optimal concentration of oat fiber preparation in rusks recipe is at 15%, regardless of the content of β-glucan in it. This concentration makes it possible to reduce the amount of acrylamide formed in baked goods and rusks by ~70% and ~60%, respectively, while maintaining the desired physical and chemical properties of the product. In addition, it was shown that the browning index and water activity strongly correlate with the content of acrylamide in rusks, which makes them good markers of this compound in rusks. The use of hydrocolloids in the form of oat fiber preparations with different contents of β-glucan as a tool for reducing the amount of acrylamide in rusks, at the same time, offers the possibility of enriching these products with a soluble dietary fiber with health properties.

Influence of seed-roasting degree on quality attributes of sunflower oil

To facilitate the typical flavor of sunflower oil, seed roasting is widely applied. In this study, the effects of seed-roasting degree (160, 180, 200°C for 0-25 min) on the quality attributes of sunflower oil were assessed, particularly tocopherols, sterols, total phenolics, fatty acids, and triglycerides composition as essential compounds for the nutritional value of the sunflower oil. Roasting seeds at a high temperature can significantly raise oxidative stability by 1.5-1.8 times, the content of carotenoids by 2.0-5.5 times, chlorophyll by 7.5-17.0 times, as well as increase the browning index by 4.0-10.0 times and deepen the color of the sunflower oil. However, the fatty acid and triglyceride profiles of sunflower oils have little change under distinct seed-roasting degrees. Synthetically considering the various indicators measured in the current study. It is recommended that the seed roasts at 160-180°C for about 20 min to ameliorate the oxidative stability and quality. Practical Application: A well-defined roasting process is very important for the food industry to be able to produce sunflower oil with desirable nutrition, unique flavor produced by the Maillard reaction and chemical properties of sunflower oil, which changes during the roasting. Considering the flavor, peroxide values, oxidation stability, and other quality attributes of oil obtained from the roasted seed, we found that sunflower seed oil better quality is obtained when roasted at 160- -180°C for about 20 min (e.g., 160°C for 20-25 min or 180°C for 15-20 min).

The Effect of Pre-Drying Treatment and Drying Conditions on Quality and Energy Consumption of Hot Air-Dried Celeriac Slices: Optimisation

Celeriac is a good source of fibre, trace minerals, and phenolic compounds; it has a pleasant aroma but is a perishable material, prone to discolouration. This research investigated the optimisation of the quality and energy demand in hot-air dried celeriac slices. The experiment utilised the I-optimal design of response surface methodology with 30 experiment runs. Pre-drying treatments (blanching at 85 °C, three minutes; dipping in 1% citric acid solution, three minutes; no pre-drying treatment), drying temperatures (50, 60, and 70 °C), air velocities (1.5, 2.2, and 2.9 m/s), and thickness (three-, five, and seven-mm) were applied. The drying conditions affected drying time significantly (p < 0.0001). The model by Midilli and others and the logarithmic model fitted best with celeriac slices drying kinetics. Blanched samples had a higher ΔE*_ab (total colour difference) and BI (browning index) but lower WI (whiteness index) than samples with other pre-drying treatments. The rehydration ratio decreased with the increase of sample thickness and blanching (p < 0.0001). A quadratic model described the specific energy consumption (E_s) best. The dried samples compared with fresh samples had increased antioxidant activity but decreased total phenolic compound value. The optimisation solution chosen was 58 °C drying temperature, 2.9 m/s air velocity, and 4.6 mm sample thickness with acid pre-drying treatment.

Improved Shelf-Life and Consumer Acceptance of Fresh-Cut and Fried Potato Strips by an Edible Coating of Garden Cress Seed Mucilage

Coatings that reduce the fat content of fried food are an alternate option to reach both health concerns and consumer demand. Mucilage of garden cress (Lepidium sativum) seed extract (MSE) was modified into an edible coating with or without ascorbic acid (AA) to coat fresh-cut potato strips during cold storage (5 °C and 95% RH for 12 days) and subsequent frying. Physical attributes such as color, weight loss, and texture of potato strips coated with MSE solutions with or without AA showed that coatings efficiently delayed browning, reduced weight loss, and maintained the texture during cold storage. Moreover, MSE with AA provided the most favorable results in terms of reduction in oil uptake. In addition, the total microbial count was lower for MSE-coated samples when compared to the control during the cold storage. MSE coating also performed well on sensory attributes, showing no off flavors or color changes. As a result, the edible coating of garden cress mucilage could be a promising application for extending shelf-life and reducing the oil uptake of fresh-cut potato strips.

The Relationship between the Browning Index, Total Phenolics, Color, and Antioxidant Activity of Polish-Originated Honey Samples

Honey is a source of sugars, amino acids/proteins, and polyphenols, which are the main substrates and reactants in the Maillard reaction. Several bioactive molecules are formed and sequestered to the brown polymeric melanoidins, resulting in a gain and loss of antioxidant function in honey. Therefore, the relationships between the browning index and total phenolic contents, color, and antioxidant activity of Polish-originated honeys, namely acacia, buckwheat, heather, linden, multiflorous, and rapeseed, obtained from three local beekeepers, were addressed in this study. The Total Phenolic Content data showed the following order: buckwheat > heather > acacia > multiflorous > linden > rapeseed. The buckwheat honey also had the highest ability to scavenge free radicals in the range of 207.1–289.3 and 40.9–52.3 µmol Trolox g⁻¹, provided by Antioxidant Compounds Water-soluble and Ferric Reducing Antioxidant Power assays, respectively. Furthermore, a higher degree of browning was observed in dark-colored honey, such as buckwheat (3.1) and heather (1.35 mAU), than in light ones. Moreover, L* and b* parameters had a greater value in the honey of multiflorous, linden, and rapeseed, and a* was higher in buckwheat and heather. The variables of browning and TPC, ACW, and FRAP were positively correlated with each other. It can be concluded that the browning index strongly contributed to parameters of honey appearance, bioactive compound content, and antioxidant activity.

Evaluation of 10 genotypes of sweetpotato for fries

The potential use of selected genotypes of sweetpotato for fries was evaluated. Moisture, fat, browning index, and beta-carotene content of fries from 10 sweetpotato genotypes, Apomuden, Bohye, Nanungungu, Otoo, CIP442162, Patron, CIP440390, Obare, Dadanyuie, and Tu-Purple, were determined by standard methods. Sensorial properties of the fries were further evaluated by an in-house trained panel of eight members using standard methods. Fat content was highest in CIP442162 and low in Dadanyuie, while beta-carotene content decreased by 44.27% in Bohye and 13.20% in Nanungungu after frying. Browning index was highest in the orange-fleshed and purple genotypes, but this was mostly due to their flesh colors and not the frying conditions. Fries from orange-fleshed genotypes, Apomuden and Nanungungu, were considered to be sweeter than the other genotypes. Detection of caramel and starch (rawness sensation) was very low for all genotypes assessed. Oily mouthcoat, moistness, and sogginess were detected in mostly the orange-fleshed genotypes, particularly Apomuden and Nanungungu. Tu-Purple, Bohye, and CIP440390 produced moderately crunchy fries and had the highest score for desirable attributes compared with the other genotypes. Tu-Purple, Bohye, and CIP440390 could be explored in commercial production of fries for enhanced utilization of developed sweetpotato genotypes.

Application of high pressure processing for shelf life extension of litchi fruits (Litchi chinensis cv. Bombai) during refrigerated storage

This study attempts to report the effect of high pressure processing (100, 200 and 300 MPa for 5, 10 and 15 min at 27 ± 2 ℃) on quality and shelf life extension of 'Bombai' variety peeled litchi fruits during refrigerated storage (5 ℃). High pressure processing significantly increased total colour difference, browning index, drip loss and total soluble solids, whereas pH decreased after processing. Also, ascorbic acid content significantly decreased after high pressure processing and retention of 83.5% was observed. Texture profile analysis showed that pressurization significantly affected firmness and increased cohesiveness, gumminess, springiness and chewiness of litchi fruits. Pressure-induced firming effect was observed at 100 and 200 MPa pressure. A maximum of 3.29, 3.24 and 3.77 log10 cycles reduction in aerobic mesophiles, yeast & mold and psychrotrophs count, respectively, was achieved after pressurization of 300 MPa for 10 and 15 min treatments. During storage, samples treated at 300 MPa for 10 and 15 min showed relatively minimal changes in physico-chemical attributes, textural parameters and maintained lower viable microbial counts. Treatments at 300 MPa for 10 min and 15 min were found to enhance the shelf life of litchi fruits up to 32 days as compared to 12 days of untreated during refrigerated storage (5 ℃).