Physical and functional properties of roselle ( Hibiscus sabdariffa L .) extract spray dried with maltodextrin‐gum arabic mixtures

Preferential Binding of Polyphenols in Blackcurrant Extracts with Milk Proteins and the Effects on the Bioaccessibility and Antioxidant Activity of Polyphenols

Milk proteins are well-known delivery agents; however, there is no clear understanding of the competitive interactions of milk proteins with polyphenols in mixed complex systems. Here, we investigate the preferential competitive interactions of different polyphenols present in blackcurrant extract with milk proteins by quantifying the protein-bound polyphenols and comparing the factors affecting these interactions. In addition, bioaccessibility and antioxidant activity were studied after in vitro gastric digestion. Our results indicated that polyphenols from blackcurrant extracts were preferentially bound to caseins more than whey proteins, with noncovalent interactions causing secondary structural changes in the protein. The hydrophobicity and the charge of the polyphenols were negatively and positively related to the number of polyphenols bound to casein and whey proteins, respectively. Moreover, the bioaccessibility and antioxidant activity of polyphenols were enhanced in the presence of milk proteins in milk-based blackcurrant samples when compared to polyphenol and protein-alone samples in the in vitro gastric phase. These findings underscore the critical role of milk proteins in encapsulating or delivering polyphenols. This will pave the way for boosting the bioavailability of polyphenols by complexing them with milk proteins and formulating functional dairy foods, integrating the beneficial effects of these compounds.

Freeze-Drying Microencapsulation of Hop Extract: Effect of Carrier Composition on Physical, Techno-Functional, and Stability Properties

In this study, freeze-drying microencapsulation was proposed as a technology for the production of powdered hop extracts with high stability intended as additives/ingredients in innovative formulated food products. The effects of different carriers (maltodextrin, Arabic gum, and their mixture in 1:1 w/w ratio) on the physical and techno-functional properties, bitter acids content, yield and polyphenols encapsulation efficiency of the powders were assessed. Additionally, the powders' stability was evaluated for 35 days at different temperatures and compared with that of non-encapsulated extract. Coating materials influenced the moisture content, water activity, colour, flowability, microstructure, and water sorption behaviour of the microencapsulates, but not their solubility. Among the different carriers, maltodextrin showed the lowest polyphenol load yield and bitter acid content after processing but the highest encapsulation efficiency and protection of hop extracts' antioxidant compounds during storage. Irrespective of the encapsulating agent, microencapsulation did not hinder the loss of bitter acids during storage. The results of this study demonstrate the feasibility of freeze-drying encapsulation in the development of functional ingredients, offering new perspectives for hop applications in the food and non-food sectors.

Polysaccharides as Carriers of Polyphenols: Comparison of Freeze-Drying and Spray-Drying as Encapsulation Techniques

Polyphenols have received great attention as important phytochemicals beneficial for human health. They have a protective effect against cardiovascular disease, obesity, cancer and diabetes. The utilization of polyphenols as natural antioxidants, functional ingredients and supplements is limited due to their low stability caused by environmental and processing conditions, such as heat, light, oxygen, pH, enzymes and so forth. These disadvantages are overcome by the encapsulation of polyphenols by different methods in the presence of polyphenolic carriers. Different encapsulation technologies have been established with the purpose of decreasing polyphenol sensitivity and the creation of more efficient delivery systems. Among them, spray-drying and freeze-drying are the most common methods for polyphenol encapsulation. This review will provide an overview of scientific studies in which polyphenols from different sources were encapsulated using these two drying methods, as well as the impact of different polysaccharides used as carriers for encapsulation.

Microencapsulation of roselle (Hibiscus sabdariffa L.) anthocyanins: Effects of drying conditions on some physicochemical properties and antioxidant activities of spray-dried powder

Anthocyanins are important phytochemical compounds in nature that are of interest not only for their health benefits such as antioxidant, anti-inflammatory, and anti-carcinogenic properties, but also for their role in imparting attractive and characteristic color to food products. In this study, anthocyanins from hibiscus (Hibiscus sabdariffa L.) calyces were microencapsulated by spray-drying technique using maltodextrin as the carrier. The experiment was carried out in the full factorial design with two factors, namely inlet temperature (150, 160, and 170°C) and anthocyanin to maltodextrin mass ratio (1:50, 1:60, 1:70, 1:80, 1:90, and 1:100) with the aim of investigating the effect of spray drying conditions on phenolic content, anthocyanin, antioxidant activity, and color of spray-dried hibiscus powder. The results showed that increasing the carrier ratio significantly reduced the antioxidant content and their activities in the powder. However, the high level of carriers exhibited a protective effect in encapsulating anthocyanin compounds into the maltodextrin matrix, which was demonstrated by high encapsulation efficiency (>85%) observed in the samples prepared at a ratio of 1:100. It should be highlighted that although high temperature (170°C) reduced total anthocyanin concentration, it actually enhanced total phenolic content. In addition, the moisture content of the powder declined with increasing carrier ratio and inlet temperature, and it was found to be in the range of 5.57%-10.19% in the powder. With solubility greater than 93.71%, the total phenolic and total anthocyanin content of spray-dried hibiscus powder were 31.5-41.9 (mg gallic acid equivalent/g of dry powder) and 6.08-10.47 (mg cyanidin-3-glucoside/g of dry powder), respectively.

Roselle (Hibiscus sabdariffa L.) calyx water extract ameliorates isoniazid and rifampicin induced liver and renal injuries in rats

Introduction: Roselle (Hibiscus sabdariffa L.) calyces possess natural antioxidants that may provide therapeutic benefits. This study aimed to investigate the protective effects of Roselle calyx water extract against isoniazid (INH) and rifampicin (RIF) induced liver and renal toxicities.Methods: Male Wistar rats (150-250 g) were designated into five groups: control group, INH-RIF group that was treated with INH-RIF at the toxic doses (50-100 mg/kg for 4 weeks, followed by 100-200 mg/kg for 2 weeks), and Roselle groups that were treated daily with Roselle extract at the doses 62.5, 125, and 250 mg/kg, respectively prior to INH-RIF administration. Blood samples were withdrawn weekly for 6 weeks before removing rats’ livers and kidneys for tissue malondialdehyde (MDA) and histopathological analysis.Results: The results showed all rats in the INH-RIF group experienced marked elevations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, and tissue MDA levels compared to the controls (P<0.05). In contrast, these biomarkers were maintained at near-normal levels in Roselle extract groups. Significant inflammation and cellular degeneration were found in the liver and renal tissues of the INH-RIF group, which were noticeably reduced with Roselle extract pre-treatment at the dose of 250 mg/kg.Conclusion: It is concluded that Roselle calyx extract can provide protection against liver and renal toxicities induced by INH-RIF administration in rats.

Technical Parameters Affecting the Spray Drying of Roselle (Hibiscus Sabdariffa) Powder

Roselle (Hibiscus sabdariffa) was a member of Malvaceae family. Its calyxes had bright red color due to presence of anthocyanin with an excellent antioxidant property. Raw roselle (Hibiscus sabdariffa L.) calyx was highly perishable due to its high moisture content. In order to diversify products from this plant, this research evaluated the possibility of spray drying for roselle extract into dried powder for long-term consumption. We focused on the effect of sugar alcohols (mannitol, sorbitol, isomalt, xylitol, erythritol) at 8%, carrier agents (maltodextrin, gum arabic, glutinous starch, whey protein concentrate, carboxymethyl cellulose) at 12%, operating parameters of spray dryer (inlet/outlet air temperature, feed rate) on physicochemical quality (bulk density, solubility, total phenolic content, total flavonoid content, anthocyanin content) of rosselle powder. Results showed that the optimal spray drying variables for rosselle powder should be 8% isomalt, 12% whey protein concentrate, inlet/ outlet air temperature 140/85oC/oC, feed rate 12 ml/min. Based on these optimal conditions, the highest physicochemical attributes of the dried roselle calyx powder would be obtained.

Fabrication of Spray-Dried Microcapsules Containing Noni Juice Using Blends of Maltodextrin and Gum Acacia: Physicochemical Properties of Powders and Bioaccessibility of Bioactives during In Vitro Digestion

Microencapsulation of fermented noni juice (FNJ) into powder format could protect bioactive compounds, reduce the unpleasant odour and improve the acceptability for consumers. Blends of maltodextrin (MD) and gum acacia (GA) were used to achieve spray-drying microencapsulation of noni juice at different blending ratios. The physicochemical properties including microstructure, moisture content, water activity, particle size, bulk/tapped density, dissolution rate, ATR-FTIR and the bioaccessibility of bioactive compounds in powders during in vitro digestion were examined. Results showed that blends produced with more GA produced microcapsules with lower moisture content, water activity and bulk/tapped density, but slower powder dissolution. The ATR-FTIR results suggested that there were no significant chemical interactions between the core material and carrier or between the MD and GA in the blend powders. The spray-dried noni juice powder produced using the blends with higher ratio of GA to MD showed a better protection on the bioactive compounds, resulting in a higher bioaccessibility of powders during in vitro digestion. This study provides insights into microencapsulation of noni juice using blends of MD and GA and examines the physicochemical properties and bioaccessibilities of spray-dried powders as affected by the selected carriers.