Study on the drying kinetics and quality parameters of osmotic pre-treated dried Satkara (Citrus macroptera) fruits

Unveiling the Influence of Osmotic Pretreatment on Dried Fruit Characteristics: A Meta-Analysis Approach

Considering the diverse findings regarding the impact of osmotic pretreatment on the quality of dried products, it is important to determine whether osmotic pretreatment can either maintain or reduce the quality of fruit products. Thus, the present study aimed to scrutinize research regarding the influence of osmotic pretreatment on the qualities of dried fruits through meta-analysis. The Scopus database was used to search for relevant articles. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses protocol, 26 studies that met the criteria for meta-analysis were identified. The presentation included statistics (mean, standard deviation, sample size) and moderator variables (fruit types, osmotic agents, solution concentrations, drying methods, and drying temperatures). After pooling data using a random effects model, the OpenMEE software was used to conduct meta-analysis. The results showed that osmo-dried fruits had significantly decreased total color difference, titratable acidity, total flavonoid content, and vitamins B1 and B3 (P<0.05) and significantly increased β-carotene and 2,2-diphenyl-1-picrylhydrazyl levels (P<0.05). Osmotic pretreatment did not affect total phenolic content and vitamin C. Subgroup analysis highlighted the influence of moderator variables on the quality of osmo-dried fruits, with each fruit responding differently to osmotic pretreatment. Moreover, using 10% sugar solution as an additive effectively enhanced the quality of dried fruits. In addition, osmotic dehydration can be combined with convective drying at a temperature of 60°C for optimal results in the drying process.

Effective drying processes for Taikor (Garcinia pedunculata Roxb.) fruit by ultrasound-assisted osmotic pretreatment: Analysis of quality and kinetic models

The present study aimed to analyze and establish an effective combination of ultrasound and immersion pretreatment processes for drying Taikor (Garcinia pendunculata Roxb.) fruits. Taikorslices were first immersed in 10 % sucrose, fructose, and glucose solution. Then, the immersed slices were treated in an ultrasonic bath at 30 °C for 10, 20, and 30 min. Drying operations were carried out at 50, 60, and 70 °C, with a fixed relative humidity of 30 %. The Page, Newton, Henderson and Pabis, and Weibull distribution models were fitted to the obtained drying data to determine the best kinetic model that effectively describes the drying properties ofTaikor. After drying operations, changes in quality parameters, e.g., β-carotene, vitamin C, B vitamins, color, antioxidant activities, and microbial loads, were measured to obtain the best drying temperature and the most effective pretreatment combination with minimum loss of nutrients of the sample. Among different kinetic models, both Page and Weibull distribution models showed the best R2 values of 0.9867 and 0.9366, respectively. The chemical properties were preserved to the greatest extent possible by drying at 50 °C with glucose pretreatment. The color parameters were better preserved by fructose pretreatment. Sonication time also had profound effect on the quality parameters of dried Taikor slices. However, higher temperature drying required a shorter time for drying and exhibited better performance in microbial load reduction. This study's findings will help to establish an effective drying condition forGarcinia pedunculatafruits.

Sonication and thermal treatment of pineapple juice: Comparative assessment of the physicochemical properties, antioxidant activities and microbial inactivation

Sonication is a novel processing method that is perceived as a substitute for heat treatment to ensure the safety of juice while reducing the loss of nutrients during processing. The impacts of sonication and thermal processing on pineapple juice, including physicochemical properties, antioxidant activities, and microbial inactivation, were studied. Pineapple juice was sonicated at 100 W and 140 W (for 5, 10 and 15 min) and heat-treated at 70 °C, 80 °C and 90 °C (for 1 min). Results indicated minor alterations in physicochemical characteristics after sonication and thermal processing, while sonication treatment showed better retention of the color, clarity, and browning index of pineapple juice. Moreover, sonication significantly increased the bioactive compounds (total carotenoids, ascorbic acid, phenolics, and flavonoids) and boosted the antioxidant activity of pineapple juice compared to the heat-processed juice. Although sonication reduced the microbial load significantly with the increasing exposure time, it could not thoroughly inactivate microorganisms like thermal treatment. Therefore, optimal sonication processing conditions are required to be determined. This study will help the food processors utilize sonication treatment in pineapple juice processing plants to inactivate microorganisms thoroughly while also boosting the nutritional value.

Innovative bio-waste-based multilayer hydrogel fertilizers as a new solution for precision agriculture

The aim of the research work was to present a multilayer hydrogel capsule with controlled nutrient release properties as an innovative fertilizer designed for sustainable agriculture. Preparation of the capsules included the following steps: sorption of micronutrients (Cu, Mn, Zn) on eggshells (1) and their immobilization in sodium alginate, with the crosslinking agent being the NPK solution (2). The capsules were coated with an additional layer of a mixture of biopolymers (0.79% alginate, 0.24% carboxymethylcellulose and 8.07% starch)by means of dipping and spraying techniques. The biocomposites were characterized by limited (<10% within 100 h for the structures encapsulated by the dipping method) release of fertilizer ions (except for small K⁺ ions). The hydrogel fertilizer formulations were analyzed for physicochemical properties such as macro- and micronutrient content, surface morphology analysis, coating structure evaluation, mechanical properties, swelling and drying kinetics. High nutrient bioavailability was confirmed in vitro (extraction in water and neutral ammonium citrate). Germination and pot tests have revealed that the application of multicomponent hydrogel fertilizers increases the length of cucumber roots by 20%, compared to the commercial product.

Dehydration and Rehydration Kinetics Modeling in the Phytochemical, Aroma, and Antioxidant Capacity of Tree Tomato Fruit Dried with Microwaves and Freeze Driers: A Comparative Study

In the present study, we investigated and compared the effect of microwaves and freeze-drying methods on the dehydration and rehydration kinetics in the phenolic, anthocyanin, aroma profiles, and antioxidant properties of tree tomato fruit (Solanum betaceum). The tree tomatoes were dried using microwaves at 350 W, 500 W, and 650 W, and then freeze-dried. The obtained drying curves were processed to find the most suitable mathematical modeling among the different moisture ratio expressions. Total phenolics, total anthocyanins, total flavonoids total carotenoids, vitamin C, Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were tested. Using High performance Liquid Chromatography (HPLC), phenolic and anthocyanin compound profiles were identified. The aroma profile was analyzed using gas chromatography-MS. The Midilli model, among others, precisely describes the dehydration methodology of all used drying methods with the coefficient of determination R2 = 0.99. On the other hand, the Weibull model precisely describes the rehydration process of the used drying methods (R2 = 0.99). Physical changes (color, shrinkage) were also studied. The freeze-dried tree tomatoes had a high number of phenolic compounds with 3.94 ± 0.26 mg GAE/g and total carotenoid compounds with 0.48 ± 0.04 µg/g. Epicathechin was the most abundant compound among the tested phenolics, followed by Cathechin. The Pelargonidin-3-glucoside was the most abundant anthocyanin whereas in freeze-dried tree tomatoes, 1.22 ± 0.01 mg/g. Fifty-four aroma compounds were detected and quantified. Among others, Eucalyptol was one of the most abundant aroma compounds analyzed in dried tree tomato fruit. Freeze-dried tree tomatoes retained most of the antioxidant and flavor compounds analyzed.

Effect of osmotic pretreatment and drying temperature on drying kinetics, antioxidant activity, and overall quality of taikor (Garcinia pedunculata Roxb.) slices

Taikor (Garcinia pedunculata Roxb.) is an underutilized, however nutritious fruit, typically found in Bangladesh and northeast parts of India. Taikor slices (1 ± 0.25 cm thickness) were pretreated for 10 min in 10% sucrose, 10% fructose, and 2% brine solution. Three different temperatures, such as 45, 50, and 55 °C were used to perform the drying operation at 30% constant relative humidity (RH). The thin-layer dehydration characteristics of taikor slices were analyzed using the Newtonian, Page, and Henderson and Pabi's model. The changes in pH, total acidity, color, β-carotene, vitamin C, B vitamins, antioxidant activity, and microbial load calculation were done to compare the comprehensive quality of untreated and pre-treated dried taikor. After assessing the coefficient of determination (R²) and root mean square error (RMSE) values, the Page model was obtained as the best-suited model. For this model, the R² and RMSE values were found to be approximately 1 and below 0.1094, respectively. Among the pretreatments, sucrose helped retain quality characteristics like ascorbic acid (115.25 ± 0.19 mg/100 g), antioxidant activity (33.25 ± 0.07%) more in the dried samples. The brine pretreated sample had minimum microbial growth. Fructose pretreated taikor samples dried at 45 °C exhibited maximum value of B vitamins (B₁ 0.025 ± 0.002 mg/100 g, B₂ 0.016 ± 0.002 mg/100 g, B₃ 0.011 ± 0.001 mg/100 g), total phenolic content (15.78 ± 0.15 mg GAE/100 g), total flavonoid content (11.11 ± 0.08 mg QE/100 g). Overall, fructose pretreated sample dried at 55 °C was found to be the best method for preserving the maximum physical and chemical quality of dried Garcinia pedunculata.