Effects of Spray-Drying Temperatures and Ratios of Gum Arabic to Microcrystalline Cellulose on Antioxidant and Physical Properties of Mulberry Juice Powder

Physical and functional stability of spray-dried jamun (Syzygium cumini L.) juice powder produced with different carrier agents

Jamun (Syzygium cumini L.) fruit is an underutilized source of bioactive phytochemicals. Therefore, preserving this fruit in various forms over the year is necessary. Spray drying can effectively preserve jamun juice; but the stickiness issue of fruit juice powder mainly arises during the drying, which may be overcome by using different carriers. Consequently, this experiment aimed to ascertain the effect of different carrier types (maltodextrin, gum arabic, whey protein concentrate, waxy starch, and maltodextrin: gum arabic) on the physical, flow, reconstitution, functional, and color stability of spray-dried jamun juice powder. The physical parameters of the produced powder such as moisture content, bulk, and tapped density were in the range of 2.57%-4.95% (w.b.), 0.29-0.50 and 0.45-0.63 g/mL, respectively. The powder yield ranged between 55.25% and 75.9%. The flow characteristics, Carr's index and Hausner ratio, were in the range of 20.89-35.90 and 1.26-1.56, respectively. Reconstitution attributes viz., wettability, solubility, hygroscopicity, and dispersibility were in the range of 90.3-199.7 s, 55.28%-95%, 15.23-25.86 g/100 g, and 70.97%-95.79%, respectively. The functional attributes include total anthocyanin, total phenol content, and encapsulation efficiency, were in the range of 75.13-110.01 mg/100 g, 129.48-215.02 g GAE/100 g, and 40.49%-74.07%, respectively. The L*, a*, and b* values ranged from 41.82 to 70.86, 14.33 to 23.04, -8.12 to -0.60, respectively. A combination of maltodextrin and gum arabic was found effective in producing jamun juice powder with appropriate physical, flow, functional, and color attributes.

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.

Anthocyanin content and storage stability of spray/freeze drying microencapsulated anthocyanins from berries: a review

A comprehensive literature search for articles published on spray and freeze-dried anthocyanins from a large variety of berries was performed. Out of a total of two-hundred and eight collected values, anthocyanin content in encapsulates had a 120-fold variation depending on the raw material and type of encapsulating agents. Highest observed anthocyanin concentration amounted to about 3500 mg/100 g powder. In most cases increasing the amount of encapsulant agents led to a noticeable reduction in the concentration of anthocyanins, this being attributable to a predominance of the dilution effect. Retention of encapsulated anthocyanins after storage at 25 °C (in darkness) for periods between 90 and 180 days were in the range of 80–67%, as long as the water activity (aw) was 0.33 or less. Some predicted values of half-time (t1/2) from literature must be taken with precaution since in many cases they were derived from experimental measurements taken at storage times smaller than predicted half times. Anthocyanin degradation during storage occurred even below the glass transition temperature (Tg) of the amorphous matrices.

Anthocyanins from Rubus fruticosus L. and Morus nigra L. Applied as Food Colorants: A Natural Alternative

Given the importance of colour in the general acceptance or rejection of a product, the use of colorants is a widespread practice, particularly in the food industry. At the same time, with the increasing consumers' awareness of the health effects that some artificial colorants can exert, there is a growing tendency to prioritize foodstuffs containing natural additives. In this work, Morus nigra L. and Rubus fruticosus L. fruit juices were characterized in terms of anthocyanins, organic acids, free sugars, and tocopherols, as also regarding their bioactive properties. Given their richness in anthocyanins, this study also aimed to prepare different solid colouring formulations by the spray-drying technique, using as stabilizers maltodextrin and arabic gum. Six free sugars and two organic acids were detected in the fruit juices, as well as the four tocopherol isoforms. Two cyanidin derivatives were found in M. nigra (cyanidin-3-O-glucoside and cyanidin-O-rhamnoside) and other four in R. fruticosus (cyanidin-O-hexoside, cyanidin-3-O-glucoside, cyanidin-O-pentoside, and cyanidin-3-O-dioxaloilglucoside). The developed colouring formulations revealed a good stability over time, in terms of anthocyanin concentration and colour parameters, and revealed to be safe for consumption, either concerning their low microbial load and lack of cytotoxicity. Thus, they represent a promising natural alternative to the massively used artificial colorants.

The effect of partial replacement of maltodextrin with vegetable fibres in spray-dried white asparagus powder on its physical and aroma properties

Asparagus concentrate was spray-dried in different carrier formulations in which maltodextrin was partially replaced by cellulose-based carriers, i.e. asparagus fibre, citrus fibre or microcrystalline cellulose. This replacement was limited to a maximum level of 3% w/w for asparagus and citrus fibres, and 10% w/w for microcrystalline cellulose, due to fibre insolubility and increased viscosity of the feed. Powders obtained from feed solutions with an initial solids content of 40% w/w showed better physical properties and aroma retention than 30% w/w. Partial replacement of maltodextrin by cellulose-based carriers resulted in powders with similar physical properties as the control and did not detrimentally influence the aroma profiles as analyzed by headspace solid-phase microextraction and gas chromatography-mass spectrometry. This research shows that fibre obtained from asparagus waste streams could potentially be used as a carrier to produce spray-dried asparagus powder with retained key asparagus volatiles such as 2-methoxy-3-isopropyl pyrazine.