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 noni fruit extract using gum arabic and maltodextrin - Optimization, stability and efficiency

Noni fruit (Morinda citrifolia L.) has many health-supporting compounds, but its biological extracts need protection against environmental impacts for stability and efficiency. To address this, microencapsulation is an advanced technology in food applications that require optimization of coating component and temperature regime. Gum arabic (GA) and maltodextrin (MD) were suitably combined at 2:1 ratio, which showed good and stable structure as well as successful microencapsulation efficiency of the enzymatic-ultrasonic assisted noni extract. A coating density of 20 % for the GA:MD formula was with highest performance. The heat setting of spray drying was optimized at 175 and 82 °C for inlet and outlet, respectively using response surface methodology with experimental validation of maximized TFC and TSC at 88.3 and 90.3 %, respectively. Noni microencapsulated powder was assessed via a series of reliably advanced techniques such as microscopy, spectrophotometry, diffraction, and calorimetry for structural properties. Noni powder was additionally tested for storage stability, heat exposure stability, and release efficiency in pH condition and in vitro digestive tract. Promising results were obtained with at least one year storage stability, better microcapsule stability at 60 and 100 °C, quite good release at pH 7.4, and suitable release efficiency in digestive tract simulation. These properties of microencapsulated noni powder open further scalability potential and various industrial applications.

Sweet tea extract encapsulated by different wall material combinations with improved physicochemical properties and bioactivity stability

Aim: To prepare sweet tea extract microcapsules (STEMs) via a spray-drying by applying different wall material formulations with maltodextrin (MD), inulin (IN), and gum arabic (GA). Methods: The microcapsules were characterised by yield, encapsulation efficiency (EE), particle size, sensory evaluation, morphology, attenuated total reflectance-Fourier transform infra-red spectroscopy and in vitro digestion studies. Results: The encapsulation improved the physicochemical properties and bioactivity stability of sweet tea extract (STE). MD5IN5 had the highest yield (56.33 ± 0.06% w/w) and the best EE (e.g. 88.84 ± 0.36% w/w of total flavonoids). MD9GA1 obtained the smallest particle size (642.13 ± 4.12 nm). MD9GA1 exhibited the highest retention of bioactive components, inhibition of α-glucosidase (96.85 ± 0.55%), α-amylase (57.58 ± 0.99%), angiotensin-converting enzyme (56.88 ± 2.20%), and the best antioxidant activity during in vitro gastrointestinal digestion. Conclusion: The encapsulation of STE can be an appropriate way for the valorisation of STE with improved properties.

Wall Materials for Encapsulating Bioactive Compounds via Spray-Drying: A Review

Spray-drying is a continuous encapsulation method that effectively preserves, stabilizes, and retards the degradation of bioactive compounds by encapsulating them within a wall material. The resulting capsules exhibit diverse characteristics influenced by factors such as operating conditions (e.g., air temperature and feed rate) and the interactions between the bioactive compounds and the wall material. This review aims to compile recent research (within the past 5 years) on spray-drying for bioactive compound encapsulation, emphasizing the significance of wall materials in spray-drying and their impact on encapsulation yield, efficiency, and capsule morphology.

In vitro bioaccessibility evaluation of pheophytins in gelatin/polysaccharides carrier

The type of carrier agent could impact pheophytin stability and bioaccessibility. Hence, it is important to have an elaborate understanding on the extent and type of pheophytin transformation during in vitro digestion of microcapsules. Four kinds of protein/polysaccharides complex were used to fabricate pheophytin microcapsules and investigated for pigments bioaccessibility. With different carriers, pheophytin pigments showed new characteristics influencing particle size and zeta potential during in vitro digestion. Pheophytin b was widely transformed to pheophorbide b, confirming pheophorbidation of the b series in proper condition. No 15¹-hydroxy lactone chlorophyll or pheophytin derivatives were detected, indicating some protective effect of microencapsulation. Pheophytins loaded in gelatin-pectin complex exhibited a relatively higher recovery rate, micellarization rate, and bioaccessibility index. The result presented in this study shows that the type of carrier agent could initiate the removal of phytyl groups in pheophytins and also inhibit or mediate their bioaccessibility.

Simulated In Vitro Digestive Characteristics of Raw Yam Tubers in Japanese Diet: Changes in Protein Profile, Starch Digestibility, Antioxidant Capacity and Microstructure

The consumption of raw yam tuber through grated yam "tororo" is a major and popular diet in Japan. However, few studies have been undertaken to evaluate the digestive characteristics of raw yam tubers. This study aimed to fill this gap by investigating the changes in the protein profile, protein and starch digestibility, antioxidant capacity and microstructure of two typical yam tubers (Nagaimo N-10 and Nebaristar) in the Japanese diet, applying a simulated in vitro digestion method. Results showed that both samples contained a considerable protein content of about 11% (dry basis) and a protein digestibility of 43-49%. The electrophoretic patterns confirmed that dioscorin was the main protein of the yam tuber, and it could be digested into peptides and free amino acids with low molecular weight during in vitro digestion. The starch hydrolysis results suggested that eating raw yam tuber cannot induce a fast glycemic increase for consumers due to a low starch digestibility of 4.4-6.1%. In addition, Nebaristar showed a higher bioaccessibility in some key amino acids and total phenolic content than the Nagaimo N-10. This study provides some essential nutritional information and simulated digestion behaviours of the raw yam tubers, which could be useful for consumers and industries when buying and processing yam tubers from the perspective of changes in the nutritional profile during digestion.

Oxidative stability and sensory evaluation of sodium caseinate-based yak butter powder

Yak butter's high unsaturated fatty acid level predisposes it to oxidation, hence must be converted into more stable forms like powder. This study aimed to spray dry yak butter using 10% yak butter and four sodium caseinate (NaCas) formulations: sample A: 100% NaCas; sample B: 50% NaCas, 50% lactose; sample C: 75% NaCas, 25% lactose; and sample D: 25% NaCas, 75% maltodextrin. The powders were vacuum and hermetically sealed, and evaluated for oxidative stability, physical and sensory properties during storage at 65 ℃ for 30 days. The results showed that samples B and D had similar and most favorable physical properties (such as, moisture, water activity, particle size, bulk density re-dispersion time, and encapsulation efficiency); though sample B, together with sample C, browned the most during storage. The majority of the sensory panelists preferred samples B and D; observed high caking in samples C and B; and the least whiteness loss and caking in samples D and A but high off-flavors in samples A and C. After storage, peroxide and thiobarbituric acid values of powder samples ranged from 34.98 to 69.54 meqO2/kg and 1.85-9.43 mg MD/kg, respectively, in the decreasing order of A, C, B, and D. Sample D, followed by B, showed the highest radical scavenging activity. Therefore, for optimum yak butter powder physical properties and oxidative stability, 50%:50%, NaCas: lactose, and 25%:75%, NaCas: maltodextrin formulations should be used. This study provides essential knowledge for butter powder processors.

Encapsulation of Bilberry Extract with Maltodextrin and Gum Arabic by Freeze-Drying: Formulation, Characterisation, and Storage Stability

Anthocyanins are polyphenolic plant pigments associated with antioxidant and health-promoting properties. However, their application in the food industry is limited due to their poor stability. The purpose of this study was to encapsulate anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract by freeze-drying and to investigate the effects of different wall materials and extract contents on the physicochemical and bioactive properties of the obtained encapsulates. Ethanolic bilberry extract was encapsulated with the use of maltodextrin (16.5–19.5 DE) (MD), gum Arabic (GA), and their combination in a 1:1 w/w ratio (MIX). Bilberry solids to wall material ratios were examined at 20:80, 30:70, and 40:60. All encapsulates showed an attractive red colour and low water activity values (aw ≤ 0.3) that indicated a low risk of microbial spoilage. In general, the biggest losses of total phenolic compounds and anthocyanins during three-week storage in the dark and at room temperature (20 ± 2 °C) were detected in the case of encapsulates with a higher content of bilberry extract (MIX30 and MIX40, and GA30 and GA40, respectively). The use of maltodextrin provided the best protection to bilberry anthocyanins during forced storage. Overall, the obtained encapsulates show suitable potential for the development of food products with added nutritional benefits.

House fly (Musca domestica) larvae meal as an ingredient with high nutritional value: Microencapsulation and improvement of organoleptic characteristics

Insects have potential to become food ingredients, but it is necessary to improve the sensory properties of insects to help them to be better accepted by the population. The purpose of this study was to produce and characterize house fly larval meal (FLM) converted to a micro-encapsulated powder to improve appearance and other organoleptic characteristics. FLM showed high protein (54%) and lipid (22%) content, with a microbiological activity compatible for food purposes. Moreover, the high content of essentials amino acids (lysine, cysteine and leucine) and unsaturated fatty acids (oleic, linoleic and palmitoleic) make FLM a valuable nutritional source. Spray drying was selected to encapsulate FLM (0.5-2% w/v) using maltodextrin (20% w/v) and alginate (0.5% w/v). Encapsulation improved the appearance of FLM, creating a white-beige, monodispersed micro-powder (9 µm in size). Micro-powder with 2% FLM is considered a good source of protein (5.1%). Microencapsulation also dramatically reduced the volatile emissions of FLM. In conclusion, novel FLM micro-powders were developed using a simple and scalable encapsulation technique. The micro-powder with 2% FLM is a good source of protein, has a pleasant appearance similar to vegetable meals and has improved odor compared to typical insect meals. Thus, insect-based food ingredients in micro-powders could become more accepted by the general population.

Protective capacity of gum Arabic, maltodextrin, different starches, and fibers on the bioactive compounds and antioxidant activity of an orange puree (Citrus sinensis (L.) Osbeck) against freeze-drying and in vitro digestion

Dehydrated fruit puree may be a convenient way to promote the healthy consumption of fruit based foods. Drying carriers, highly used by the food industry to stabilize dried fruit products, may show a potential encapsulating capacity of the biocompounds, that could also limit their bioaccesibility. This study analyzed the impact of gum Arabic (GA), bamboo fiber (BF), native corn starch, starch substituted with octenylsuccinic groups, pea fiber, and maltodextrin on the in vitro bioaccessibility of vitamin C (VC), total phenols (TP), and β-carotene, as well as on the antioxidant capacity during the freeze-drying and in vitro digestion of an orange puree. Amongst the formulations studied, GA + BF was the most effective for phytochemicals protection of the freeze-dried orange puree during the intestinal stage of digestion, resulting in a higher TP and VC bioaccessibility (59% and 36%, respectively).

Membrane Disruption Properties of Essential Oils—A Double-Edged Sword?

The emerging literature has suggested essential oils (EOs) as new possible weapons to fight antimicrobial resistance due to their inherent antimicrobial properties. However, the potential pharmaceutical use of EOs is confronted by several limitations, including being non-specific in terms of drug targeting, possessing a high cytotoxicity as well as posing a high risk for causing skin irritation. Furthermore, some EOs have been demonstrated to adversely affect the cellular lipid profiles and permeability of the cell membrane, which may result in undesirable outcomes for the cells. Nevertheless, owing to their naturally complex compositions, EOs still hold undiscovered potential to mitigate antimicrobial resistance, as an alternative to existing antibiotics. To address the issue of overuse in antibiotics for crops which have led to the growing threat of antimicrobial resistance globally, EOs have also been proposed as potential biopesticides. Since the perceived advantages of antimicrobial attributes in EOs remain largely unexplored, this review aims to provide a discourse into its current practical usefulness in the agricultural setting. Finally, updated bioengineering techniques with emphasis of the biopesticide potential of EOs as a means to alleviate antimicrobial resistance will be included.

Comparing Three Types of Mandarin Powders Prepared via Microfluidic-Jet Spray Drying: Physical Properties, Phenolic Retention and Volatile Profiling

This study aimed to offer an alternative way for delivering the benefits of the mandarin fruit juice to consumers via spray drying microencapsulation. Two mandarin cultivars, Afourer (A) and Richard Special (RS), were studied. Three types of juice sample were prepared, i.e., the whole fruit juice (A3 & RS3), the flavedo-removed fruit juice (A2 & RS2), and the peel-removed fruit juice (A1 & RS1) samples. Gum Acacia and maltodextrin (ratio of 1:1, w/w) were chosen as wall matrices for aiding the drying of the juice samples while using a microfluidic-jet spray dryer. The properties of the fruit powder (colour, water activity, bulk/trapped density, solubility, hygroscopicity, morphology) and the retention of major phytochemicals (i.e., phenolic and volatile compounds) were examined. The results showed that the powders produced from the whole fruit juices (A3 and RS3) gave higher yellow colour with a regular winkled surface than other powders (A1 & RS1, and A2 & RS2). The water activity of mandarin powders was in a range of 0.14 to 0.25, and the solubility was around 74% with no significant difference among all of the powders. The whole fruit powders had a significantly higher concentration of phenolic compounds (A3, 1023 µg/100 mg vs. A2, 809 µg/100 mg vs. A1, 653 µg/100 mg) and aroma compounds (A3, 775,558 µg/L vs. A2, 125,617 µg/L vs. A1, 12,590 µg/L). This study contributed to the delivery of phenolic and flavour compounds of the mandarin fruits, at the same time minimising waste generation during processing. It also gave insight into the production of spray-dried powders from the whole mandarin fruits.