How Do the Different Types of Carrier and Drying Techniques Affect the Changes in Physico-Chemical Properties of Powders from Chokeberry Pomace Extracts?

Effect of dipping pre-treatments and drying methods on Aronia melanocarpa quality

This study examined the impact of different dipping pre-treatments (PO: potassium carbonate-olive oil emulsion, HW: hot water) and drying methods (sun, oven, hot air, and freeze) on aronia berry quality. Freeze-drying showed the highest process yield (29.07%-29.43%), while sun-drying had the lowest (24.60%-25.74%). PO pre-treatment showed superior moisture and water activity reductions across all drying methods. Notably, it enhanced carotenoid levels (PO: 399.5, HW: 371.4 mg BCE/kg), antioxidant activity (PO: 9602.8, HW: 9403.3 mg TE/kg), total phenolics (PO: 38176.5, HW: 34804.0 mg GAE/kg) and flavonoids (PO: 6537.1, HW: 6141.5 mg CE/kg) during freeze-drying. Additionally, PO-treated samples exhibited superior rehydration properties, with a ratio of 293.32% and a 1.01 g/g capacity. On the other hand, HW pre-treatment increased ascorbic acid levels (PO: 377.0, HW: 391.7 mg/kg). The highest quality dried aronia berries are generally observed in PO-treated samples, especially in freeze drying, followed by hot-air, oven, and sun drying processes.

Extraction-depended and thermally-modulated physical and chemical properties of powders produced from cranberry pomace extracts

Recovering bioactives from botanical by-products in the form of powders has been attempted through a number of multidirectional approaches. Yet understanding the processing of such plant formulations requires dedicated research owing to the manifold factors shaping the quality of powders. Therefore, the study aimed at production of cranberry powders from pomace extracts and to evaluate how different solvent type, carriers and drying techniques modulate their physico-chemical properties. Freeze- and vacuum drying significantly differentiated samples in terms of physical properties, while the extraction solvent and carrier type had substantial impact on chemical ones. For carrier-added products pomace extraction with acidified 50% ethanol resulted in the highest content of identified phenolics in powders (up to 5.87 g · 100 g-1 dry matter), while 30% acetone in the lowest (on average, 3.94 g · 100 g-1 dry matter). Acetone extraction strengthened the formation of hydroxymethyl-L-furfural that was higher when compared to acidified 50% ethanol, while trace amounts were reported for non-acidified counterpart. Similar observation was made in the case of flavan-3-ols. Addition of carriers during powders production led to the lower hydroxymethyl-L-furfural formation even down to 74% with regard to carrier-free samples. The study confirmed feasibility of managing cranberry pomace into high-value powders in extraction-depended and thermally-modulated quality matter.

The Influence of the Vacuum Impregnation, Beetroot Juice, and Various Drying Methods on Selected Properties of Courgette and Broccoli Snacks

The drying process is used in the food industry to extend the shelf life of fruits and vegetables without the use of preservatives. As quality, visual, and aroma characteristics are important determinants of consumer interest, they play a key role in the development of new foods. In the present study, vacuum impregnation (VI) was used prior to vacuum drying (VD) and freeze drying (FD) of courgette and broccoli. Organic beet juice was used to produce the novel snacks. The study showed that the use of vacuum impregnation significantly affected the VOCs profile (volatile organic compounds profile), in which the following compounds were found: viz: 2-(E)-hexen-1-ol, 2-(Z)-hexen-1-ol and aceto-phenone. VI caused a decrease in volumetric gel index (VGI), drying shrinkage (S), water activity (AW), decreased color saturation (∆C), and increased dry matter content (DM). All these properties testify to the positive effect of the pretreatment used. The drying methods used had a significant effect on the properties of the dried vegetables. The dries obtained by the FD method showed higher density and water activity, as well as better preserved color (lower ∆E) and higher VOCs, so it is considered that freeze drying is a suitable method for obtaining novel courgette and broccoli snacks.

Extraction of gymnemic acid from Gymnema inodorum (Lour.) Decne. leaves and production of dry powder extract using maltodextrin

The aim of the present study was to maximize the extraction of gymnemic acid (GA) from Phak Chiang Da (PCD) leaves, an indigenous medicinal plant used for diabetic treatment in Northern Thailand. The goal was to overcome the low concentration of GA in the leaves, which limits its applications among a larger population and develop a process to produce GA-enriched PCD extract powder. The solvent extraction method was employed to extract GA from PCD leaves. The effect of ethanol concentration and extraction temperature were investigated to determine the optimum extraction conditions. A process was developed to produce GA-enriched PCD extract powder, and its properties were characterized. In addition, color analysis (L*, a*, and b*) was performed to evaluate the overall appearance of the PCD extract powder. Antioxidant activity assay was conducted to assess the ability of the PCD extract powder to neutralize DPPH free radicals. The results showed that the concentration of 50% (v/v) ethanol at 70 °C for 2 h resulted in a higher GA concentration of 8307 mg/kg from dried PCD leaves. During the drying process, the use of maltodextrin at a concentration of 0.5% (w/v) was found to produce PCD extract powder with the maximum GA concentration. The color analysis revealed that the PCD extract powder had a dark greenish tint mixed with yellow. The antioxidant activity assay showed that 0.1 g of PCD extract powder was able to neutralize 75.8% of DPPH free radicals. The results concluded that PCD extract powder could potentially be used as a source of nutraceuticals or as a functional food ingredient. These findings suggest the potential value of GA-rich PCD extract powder in various applications in the pharmaceutical, nutraceutical, or food industries.

Juice Powders from Rosehip (Rosa canina L.): Physical, Chemical, and Antiglycation Properties

Fruits from rosehip (Rosa canina L.) are gaining popularity due to their content and profile of bioactive components. Rosehip is distinct for its antioxidant, immunomodulatory, and anticancer properties. However, the abundance of these bioactives led to a tart taste, resulting in its consumption mainly in processed form. Due to microbiological safety, pasteurization is the preferred way of processing, which affects the chemical properties of the juice. A promising approach to improve acceptability of rosehip's physical properties, while preserving its bioactive compounds and adding health-promoting benefits, is to enrich the rosehip juice with functional carriers before drying. The influence of the carrier type (maltodextrin, inulin, trehalose, palatinose) and drying technique (spray- and freeze-drying) on the physical, chemical, and antioxidant properties of pasteurized, and non-pasteurized juice powders was examined in this study. In addition, the ability of powders with functional carriers to inhibit protein glycation was evaluated. Spray drying led to products with improved physical properties in relation to freeze-drying. The addition of carrier substances significantly influenced the antioxidant capacity determined by TEAC ABTS and FRAP methods, whereby the application of inulin and palatinose retained antioxidant capacity better than the frequently used maltodextrin. Moreover, rosehip juice powders showed a promising ability to inhibit protein glycation.

Predicting the Moisture Ratio of a Hami Melon Drying Process Using Image Processing Technology

For food drying, moisture content and shrinkage are vital in the drying process. This paper is concerned with the moisture ratio modeling and prediction issues of the Hami melon drying process. First, an experimental system was developed; it included an adjustable-power microwave drying unit and an image-processing unit. The moisture contents and the areas of Hami melon slices at different times were sampled in real time. Then, the expression of the moisture ratio with regard to shrinkage was derived by using the Weierstrass approximation theorem. A maximum likelihood fitness function-based population evolution (MLFF-PE) algorithm was then put forward to fit the moisture ratio model and predict the moisture ratio. The results showed that the proposed MLFF-PE algorithm was effective at fitting and predicting the moisture ratio model of the drying process of Hami melon slices.

Thermal and Non-Thermal Treatments to Preserve and Encourage Bioactive Compounds in Fruit- and Vegetable-Based Products

Fruit- and vegetable-based products (F&Vs) have been conventionally processed using thermal techniques such as pasteurization, scalding, or/and drying, ensuring microbial safety and/or enzyme deactivation [...].

Micro-Encapsulation of Phytochemicals in Passion Fruit Peel Waste Generated on an Organic Farm: Effect of Carriers on the Quality of Encapsulated Powders and Potential for Value-Addition

The passion (Passiflora edulis Sims) fruit peel is rich in phenolics and other bioactive compounds and has great potential as a natural food preservative. The present study investigated the value-adding potential of passion fruit peel waste generated on an organic farm. The effect of carriers in encapsulating the peel extract to develop a polyphenolic-rich powder was investigated. The passion fruit peel extracts were prepared using 70% ethanol (1:10 w/v), and encapsulated using waxy starch (WS), gum arabic (GA), and maltodextrin (MT) before freeze-drying. The effects of carriers on the passion fruit peel powder (PFPP) production yield, physicochemical, rheological, phytochemical, and antioxidant properties were investigated. GA-and MT-encapsulated powders had better physical, phytochemical, and antioxidant properties, including yield, total soluble solids, solubility, bulk density, total phenolic content, and ferric reducing antioxidant powder. A total of 18 metabolites, including phenolic acids (10), flavonoids (6), and stilbenes (2), were tentatively identified in all the PFPP samples, with WS exhibiting a higher concentration of the compounds compared to GA and MT. Our results indicated that no single carrier was associated with all the quality attributes; therefore, better results could be produced by compositing these carriers. Nonetheless, our results highlight the potential of passion fruit peels as a source of polyphenols and functional ingredient in formulating natural food additives.