Evaluation of physicochemical, sensory, and antimicrobial properties of small-scale produced fruit vinegars

Hungarian fruit vinegars were characterised in terms of physicochemical attributes (total polyphenol content, antioxidant characteristics/FRAP, CUPRAC, ABTS/, ascorbic acid content, pH, total soluble solids), sensory profiles, and antimicrobial properties. Both compositional and sensory profiles showed distinct patterns depending on the type of vinegar (Tokaj wine, balsamic or apple) and the additional fruit used. Balsamic vinegars maturated on rosehip, sea buckthorn, and raspberry showed outstanding antioxidant performances. Rosehip, raspberry, and quince vinegars, as well as vinegars produced from Tokaji aszú and balsamic apple obtained high scores for fruity and sweet notes. Antimicrobial activities were tested on Gram-negative and Gram-positive organisms, including probiotic bacteria. Generally, only weak activities were obtained, which was attributed to the natural sugar content of the samples, depending on the type of the vinegar and the fruit. Similar results, but more pronounced bacterial growth inhibitions were obtained for probiotic strains, however, some probiotic strains were resistant to at least two of the vinegars. Based on these, balsamic apple, raspberry, rosehip, quince, and sea buckthorn may qualify as potential functional components of probiotic preparations containing some of the strains tested.

Effect of Brine fermented Pickling to Physicochemical, Anti-nutritional, and Microbiological Attributes of Pickled gboma Eggplant (Solanum macrocarpon)

Gboma eggplant (Solanum macrocarpon) has low calorie, high phenolic and antioxidant, excellent dietary fibre and mineral content. Besides healthy effects, gboma eggplant also contained numerous anti-nutrients unbeneficial for human health. Due to high moisture content, gboma eggplant was highly perishable during post-harvest. This research observed the changes of nutritional proximate, mineral contents, acidification indexes, anti-nutrients, phytochemical and antioxidant properties, texture profiles, microbiological characteristics of both raw and pickled gboma eggplant. Gboma eggplant fruits were soaked in clean water for 2 minutes before cutting their calyx lobes. The pre-treated fruits were submerged in sterilized brine (5% salt) for 8 days. Periodically, pickled samples were taken to examine physicochemical, anti-nutritional, and microbiological attributes of pickled gboma eggplant. Results showed that nutritional proximate of moisture, ash, protein, fat, fibre, carbohydrate was varied slightly during fermentation. There was a decreasing trend of moisture and carbohydrate; meanwhile, there was an increasing trend of ash, protein, fibre during 8 days of fermentation. There was no significant difference of fat during pickling. There was a minor increment of mineral contents in all samples. There was accumulation of phenyllactic acid, ascorbic acid content and titratable acidity with exception of pH. Anti-nutrient contents like tannin, phytate, oxalate, steroidal glycoalkaloid greatly decreased in raw and pickled eggplant. Remarkable increments of total phenolic, flavonoid, DPPH free radical scavenging and FRAP ferric reducing antioxidant of raw and pickled eggplant was presented. Texture profiles of hardness, crispness, fracturability, crunchiness revealed a minor reduction of sensory scores during 8 days of fermentation. Lactic acid bacteria, Bacillus significantly proliferated; meanwhile, Micrococcus and S. aureus were absolutely retarded in pickled eggplant. Yeast and fungi increased in the first 4 days and decreased afterwards. There was no significant difference of proximate compositions; mineral contents; phenyllactic acid, ascorbic acid content, pH and titratable acidity; anti-nutritional contents; phytochemical and antioxidant properties; texture profile (sensory score); microbiological load (with exception of S. aureus) between pickled gloma eggplants at day 6th and day 8th of fermentation. At a quick glance, the length of fermentation could be shorted to 6 days instead of 8 days. However, at the 6th day, S. aureus load was still presented at 0.33±0.01 log CFU/g. The fermentation should be lasted to 8th day so that S. aureus load could be dropped down to zero to ensure microbial food safety. Raw gboma eggplant should be fermented in 8% brine solution for 8 days to obtain the best physicochemical, anti-nutritional, and microbiological properties of pickle. Findings of this research suggested that fermentation pickling would be an appropriate approach to improve nutritional, physicochemical and functional criteria while controlling toxic chemical residues, retarding the growth and proliferation of spoilage and pathogen microorganisms.

Influence of probiotics on physico-chemical and organoleptic characteristics of sweet orange juice

Aim: The study was undertaken to evaluate the survival probiotic organisms and its influence on the physical, chemical, nutritional and sensory characteristics of sweet orange juice. Methodology: Two samples of probiotic juice were prepared with 10 percent innoculum containing LAB strains (Lactobacillus bulgaricus and Lactobacillus plantarum). Sample A (without encapsulated strains) and Sample-B (with encapsulated strains) were prepared and incubated for 10hrs at 35oC. After incubation, the physico-chemical analysis of both the samples were analyzed for TSS, pH, acidity, total sugars, reducing sugars and ascorbic acid content. Results: The results of TSS, pH, acidity, total sugars, reducing sugars and ascorbic acid content for sample –A and Sample –B were 11.4˚Brix, 3.51, 0.82 percent, 6.1 percent, 1.5 percent, 4.6 percent, 40mgml-1 and 11.6˚ Brix, 3.68, 0.77 percent, 6.4 percent, 1.7 percent, 4.9 percent, 40 mg ml-1, respectively. Sensory evaluation revealed that overall acceptance of probiotic juice containing encapsulated strains and free strains in the first week was 8.3 and 7.8, respectively. Even after 4 weeks of storage, the overall acceptance for juice with encapsulated strains was better than free strains with a score of 7.5 and 7.0 at the end of storage period. Interpretation: The sweet orange juice with encapsulated strains has high viable cell count (109cfu ml-1) even after 4 weeks of storage resulted in stable therapeutic probiotic sweet orange juice. It is further, suitable for commercial production of probiotic sweet orange juice with probiotic cultures.

Development and effectiveness of greenhouse type solar dryer for coriander leaves

Aim: Sun drying system is not able to provide the best drying performance and quality dried produce of leafy vegetables. To facilitate better options to the farmers, this study aims to develop and evaluate a cost-effective greenhouse type solar dryer to improve shelf stability of coriander leaves. Methodology: A greenhouse type solar dryer (5m x 3m x 2.3m) was developed with the provision of rigid frame, 200 µ UV stabilized LDPE glazing material, solar collector cum drying chamber, inlet air and outlet air openings. The dryer was evaluated for its performance, drying characteristics of coriander leaves and qualitative evaluation of dried product as compared to open sun drying. Results: The greenhouse type solar dryer performed well for coriander drying with increased level of temperature inside the dryer (42oC) and 24% reduced drying time as compared to sun drying (29oC).The loading capacity, efficiency, payback period and B:C ratio of the dryer were found to be 100 kg, 70.47 %, 1.26 yr and 1.79, respectively. The drying of coriander leaves occured mostly in falling rate period. Coriander leaves dried under the dryer possessed higher values of chlorophyll content (1.356 mg g-1 of tissue), ascorbic acid content (111.257 mg 100g-1), rehydration ratio (5.302) and coefficient of rehydration (0.762) than sun dried coriander leaves with the respective values of these quality parameters being 1.097 mg g-1 of tissue, 62.37 mg 100g-1, 4.715 and 0.689, respectively.

Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties

Background: Prickly pear juices are considered as valuable ingredient for sports and energy drinks due to its higher amino acids contents, minerals and attractive red color. Hence, prickly pear fruit has received renewed interest for the production of juice. Up to date, relatively little work has been reported regarding the manufacturing of prickly pear products. Enzyme has proved to be the key element for producing clear and stable fruit juice. The present study aimed to optimize the processing parameters for enzymatic clarification of prickly pear juice. The results of this investigation are expected to provide the suitable process technology for the production of prickly pear juice with better retention of betalain content and color value. Methods: Prickly pear pulp was treated with pectinase enzyme at different concentrations (0.01-0.09%), incubation temperatures (40-60°C) and incubation time (60-180 min). The effect of enzymatic treatments on clarity, color index, betalain content and ascorbic acid content of juice were studied through response surface methodology by employing second order central composite rotatable design. Result: Response surface analysis determined the optimum condition for clarifying prickly pear juice as 0.036% enzyme concentration, 46°C incubation temperature and 112 min incubation time. At this condition, it was predicted to produce the prickly pear juice with clarity of 48.59% T, color index of 0.603 abs, betalain content of 542.93 mg/L of juice and ascorbic acid content of 9.35 mg/100 g with the desirability of 0.780.

Berries and Leaves of Actinidia kolomikta (Rupr. & Maxim.) Maxim.: A Source of Phenolic Compounds

Berries of Actinidia kolomikta (A. kolomikta) are known for high ascorbic acid content, but the diversity of phenolic compounds has been little studied. The present research aimed to investigate phenolic compounds and antioxidant activity in berries and leaves of twelve A. kolomikta cultivars. The UHPLC-ESI-MS/MS technique was used to determine differences among cultivars in the quantitative composition of individual phenolic compounds. Antioxidant activity was determined by DPPH• free radical scavenging and CUPRAC methods. In the present study, 13 phenolic compounds were detected in berries, whereas leaves contained 17 phenolic compounds. Flavonols were the primary class found in both berries and leaves; other identified phenolic compounds were flavan-3-ols, flavones and, phenolic acids; and dihydrochalcone phloridzin was identified in the leaves. The amount and variety of phenolic compounds in berries and leaves and antioxidant activity were found to be cultivar-dependent. The highest total content of phenolic compounds was found in the leaves of the cultivar ‘Aromatnaja’ and in the berries of the cultivar ‘VIR-2’. Results of this study have confirmed that berries and leaves of A. kolomikta could be a valuable raw material for both food and pharmaceutical industries.

A Novel Technique Using Advanced Oxidation Process (UV-C/H2O2) Combined with Micro-Nano Bubbles on Decontamination, Seed Viability, and Enhancing Phytonutrients of Roselle Microgreens

Microbial contamination commonly occurs in microgreens due to contaminated seeds. This study investigated the decontamination effects of water wash (control), 5% hydrogen peroxide (H2O2), UV-C (36 watts), advanced oxidation process (AOP; H2O2 + UV-C), and improved AOP by combination with microbubbles (MBs; H2O2 + MBs and H2O2 + UV-C + MBs) on microbial loads, seeds’ viability, and physio-biochemical properties of microgreens from corresponding roselle seeds. Results showed that H2O2 and AOP, with and without MBs, significantly reduced total aerobic bacteria, coliforms, Escherichia coli (E. coli), and molds and yeast log count in seeds as compared to the control. Improved AOP treatment of H2O2 + UV-C + MBs significantly augmented antimicrobial activity against total bacteria and E. coli (not detected,) as compared to control and other treatments due to the formation of the highest hydroxy radicals (5.25 × 10−13 M). Additionally, H2O2 and combined treatments promoted seed germination, improved microbiological quality, total phenolic, flavonoids, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) activity of the grown microgreens. Ascorbic acid content was induced only in microgreens developed from H2O2-treated seeds. Single UV-C treatment was ineffective to inactivate the detected microorganism population in seeds. These findings demonstrated that improved AOP treatment (H2O2 + UV-C + MBs) could potentially be used as a new disinfection technology for seed treatment in microgreens production.

Effect of Ultrasound and Enzymatic Mash Treatment on Bioactive Compounds and Antioxidant Capacity of Black, Red and White Currant Juices

Ultrasound treatment is recognized as a potential technique for improvement in the nutritional values of fruit juices. This study was initiated with the objective of evaluating bioactive compounds and some important quality parameters of black (BC), red (RC) and white (WC) currant juices obtained from fruit mash preliminarily treated by enzymes combined with ultrasound. Individual and total phenolic content (TPC), anthocyanins, color parameters, ascorbic acid, antioxidant capacity (TEAC), juice yield, pH, titratable acidity, and soluble solids were investigated. Significant increases in the levels of TPC and antioxidant capacity of sonicated samples were observed. However, ultrasound treatment had no effect on individual phenolic compounds of juices. Sonication of mash before juice pressing did not cause any noticeable changes in ascorbic acid content. Only in the case of WC was an increase in content of vitamin C noticed. The color of juices obtained after treatment was similar to the control sample. It was demonstrated that enzymatic combined with ultrasound treatment of mash for different colored currant fruit did not have any dismissive effect and could even improve some parameters of the juice obtained.

Phenotypic Diversity and Association Mapping of Ascorbic Acid Content in Spinach

Ascorbic acid (AsA), or vitamin C, is an essential nutrient for humans. In plants, AsA functions as an antioxidant during normal metabolism or in response to stress. Spinach is a highly nutritious green leafy vegetable that is consumed fresh, cooked or as a part of other dishes. One current goal in spinach breeding programs is to enhance quality and nutritional content. However, little is known about the diversity of nutritional content present in spinach germplasm, especially for AsA content. In this study, a worldwide panel of 352 accessions was screened for AsA content showing that variability in spinach germplasm is high and could be utilized for cultivar improvement. In addition, a genome-wide association study for marker-trait association was performed using three models, and associated markers were searched in the genome for functional annotation analysis. The generalized linear model (GLM), the compressed mixed linear model (CMLM) based on population parameters previously determined (P3D) and the perMarker model together identified a total of 490 significant markers distributed across all six spinach chromosomes indicating the complex inheritance of the trait. The different association models identified unique and overlapping marker sets, where 27 markers were identified by all three models. Identified high AsA content accessions can be used as parental lines for trait introgression and to create segregating populations for further genetic analysis. Bioinformatic analysis indicated that identified markers can differentiate between high and low AsA content accessions and that, upon validation, these markers should be useful for breeding programs.