Antibacterial mechanisms of star anise essential oil microcapsules encapsulated by rice protein-depolymerized pectin electrostatic complexation and its application in crab meatballs.

A mixed solid matrix of the depolymerized pectin (DP) and rice protein (RP) were investigated to improve the antibacterial activity of star anise essential oil (SAEO) through microencapsulation. The encapsulation was undertaken via electrostatic complexation method followed by spray drying. Under the optimized conditions, SAEO microcapsules with 92.2 % encapsulation efficiency was acquired at 3:2 of DP-to-RP, 1:3 of DP-to-SAEO and pH 4.0. DP-RP/SAEO microcapsules exhibited a spherical-shaped particle with smaller particle size, and sustained release. FTIR and morphology analysis confirmed that SAEO was successfully encapsulated in the solid matrix of microcapsules. DP-RP/SAEO microcapsules caused the destruction of cytomembranes and reduction of membrane proteins, which led to the alteration of cell membrane fluidity and integrity. Meanwhile, DP-RP/SAEO microcapsules repressed the key enzyme in tricarboxylic acid (TCA) and Hexose monophosphate pathway (HMP) cycle pathway of E. coli, S. aureus. The application experiments indicated DP-RP/SAEO microcapsules can effectively control the growth of E. coli and S. aureus in crab meatballs.

Evaluation of alginate-biopolymers (protein, hydrocolloid, starch) composite microgels prepared by the spray aerosol technique as a carrier for green tea polyphenols.

Effects of low methoxyl pectin, milk protein concentrate (MPC), and waxy starch on the encapsulation of green tea-polyphenols in alginate gels produced using spray aerosol technique were evaluated. MPC and waxy starch treated first by cold-renneted induced gelation method and gelatinization method, respectively. DSC thermal analysis and FTIR spectroscopy were used to prove the presence of polyphenols in gel matrixes. The encapsulation efficiency (%EE) and the polyphenols release were investigated using Folin-Ciocalteu assay. The results showed that the addition of biopolymers into alginate gels increased the encapsulation efficiency (%EE) but reduced the release percentage of polyphenol in water and simulated gastric fluid (SGF). Among the three biopolymers, cold-renneted MPC gave the best protection for polyphenols encapsulated in alginate microgels. It increased %EE from 63% to 68% in fresh gels, reduced the release percentage in water from 72% to 62% and reduced the release percentage in SGF from 76% to 67%.

Incorporation of probiotics (Bifidobacterium animalis subsp. Lactis) into 3D printed mashed potatoes: Effects of variables on the viability.

3D printing is an emerging technology with the potential to revolutionize people's eating habits. This study firstly optimized the mashed potatoes (MP) formulation and correlated its 3D performance with rheological properties. Yield stress and consistency index (K) were closely related with MP's extrusion behavior, and too high values of them (like 2558 Pa and 2794 Pa·sn) caused the difficulty in extrusion process. Yield stress and elastic modulus (G') were critical to MP's self-supporting performance and too low values of them resulted in the deformation of printed parts during storage. The feasibility of incorporation of probiotics (Bifidobacterium animalis subsp. Lactis BB-12) into 3D printed mashed potatoes (MP) was then studied. MP with probiotics was printed with different nozzle diameter (0.6, 1.0 and 1.4 mm), printing temperature (25, 35, 45 and 55 °C) and evaluated for survival during extrusion and storage at 5 °C. It was found only the small nozzle diameter (0.6 mm) resulted in the reduction of probiotic viability from 9.93 log CFU/g to 9.74 log CFU/g. Greater reduction of viable counts of probiotics (from 10.07 log CFU/g to 7.99 log CFU/g) was found when the MP was held in a heating nozzle barrel at 55 °C for 45 min. No significant difference of probiotics viability in 3D printed samples was found during 12-day storage period at 5 °C. This study provides a new dimension on the development of functional foods by 3D printing.

Edible flowers: Review of flower processing and extraction of bioactive compounds by novel technologies.

Edible flowers have a long history of consumption in the form of vegetable flowers, fruit flowers or aromatic flowers. Because of their colorful and flavorful nature, edible flowers are believed to contain various nutritional and bioactive components. Today, people are advocating to eat nutritious food and paying attention to healthy foods, flower foods have become a new fashion diet trend. Although edible flowers have great sensory attraction, they have not used in food yet as widely as fresh vegetables and fruits have. The extremely short shelf-life limits the commercial use of edible flowers. In order to find some novel processing technologies which can extend the shelf-life and ensure the commercial use of flowers, we summarized the data of more than 100 studies performed until now on edible flowers. This review concludes emerging technologies including modified atmosphere packaging, high hydrostatic pressure, irradiation and edible coating to keep flower fresh, drying technologies including microwave drying, freeze drying and hybrid drying to maintain the optimal state of flower materials, as well as different extraction methods to extract the bioactive compounds and the microencapsulation of these compounds.

Dielectric properties of carrots affected by ultrasound treatment in water and oil medium simulated systems.

The ultrasound treatment of vegetables can damage their tissue structure and release water and soluble solids altering the dielectric properties of the material. Changes in the dielectric properties will influence the microwave processing of ultrasound pretreated material. In order to investigate the effect of ultrasound pretreatment on dielectric properties, carrots were ultrasonicated in simulated water and oil systems. Microwave heating and microwave-assisted vacuum frying of carrot slices were also completed to explore the relation between dielectric properties of microwave pretreated samples and microwave absorption. Ultrasound of carrots in water simulated system showed that ε' and ε″ of carrots tended to decrease with the increase of ultrasonic power (from 480 W to 640 W) and time (from 10 min to 30 min). Ultrasound treatment of carrots in salt solutions increased ε' and ε″ of carrots. The combined pretreatment of microwave blanching with ultrasound in salt solutions increased ε″ (from 19.72 to 29.90). Conversely, in oil simulated system, the ε' and ε″ of carrots also decreased as the ultrasonication power and time increased. Besides, the dielectric properties decreased as the temperature of oil medium increased from 35 °C to 75 °C. With improved dielectric properties, the dehydration rate during frying of carrot increased due to the enhanced microwave absorption. Therefore, the combined pretreatment of microwave blanching with ultrasound in salt solutions largely improved the dielectric properties of carrots, and reducing the required time of microwave vacuum frying.

Creation of internal structure of mashed potato construct by 3D printing and its textural properties.

3D printing was used for printing mashed potatoes (MP) constructs with variable internal structures. The dimensional properties, textural and structural qualities of the printed objects were investigated as a function of infill levels (10, 40 and 70%), infill patterns (rectilinear, honeycomb and hibert curve), and number of shell perimeters (3, 5 and 7). The printed samples significantly matched the designed geometries. Hardness and gumminess were strongly related to infill levels and perimeters, but the printing paths being performed to fill the samples showed no effect on them. Firmness and Young's modulus were only affected by infill percentage but not by perimeters and printing paths. Further, comparative assessment of 3D printed and cast samples were also conducted on the textural properties and microstructure features. Microstructure analysis indicated a uniform internal structure was obtained for cast sample. In comparison, an obvious layered structure was observed in longitudinal-sectional direction while a porous structure was obtained in cross-sectional view of 3D printed samples regardless of infill levels. 3D printed samples, even at 100% infill, were significantly (p < .05) less hard, by up to 26.75% and 28.36% in terms of hardness and gumminess, compared to cast samples. The results suggest that 3D printing considerably changes the properties of printed samples, possibly offering a new way for tailoring textural properties of printed samples through creating their internal structure.

Effect of gums on the rheological, microstructural and extrusion printing characteristics of mashed potatoes.

This paper studied the rheological, microstructural and 3D printing characteristics of mashed potatoes (MP) with gums of xanthan (XG), guar (GG), k-carrageenan (KG) and k-carrageenan- xanthan gum blend (KG-XG). Addition of gums increased the viscosity, storage modulus (G'), and loss modulus (G″) of MP except XG. Creep results indicated that self-supporting performance followed decreasing order of KG > KG-XG > GG > contorl > XG. Fourier Transform infrared spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR) results well explained the behavior by enhancing hydrogen bonding and constraining water molecules' mobility. KG-MP samples possessed good self-supporting performance but with rough surface and lots of defective points. The parts printed using XG-MP were "fatter" than target objects but with a smooth surface structure. This probably because the excellent extrudability (more fluid-like behavior, tanδ 0.185) but with poor self-supporting ability indicated by lower G' and greater creep strain 0.88%. The printed objects using KG-XG-MP possessed a smooth surface structure (visual appearance), and good printing precision indicated by the lowest dimensional printing deviation for a printed cuboid shape (2.19%, 2.20%, 2% for length, width, height direction, respectively). This was probably because the creaminess effect provided by XG render the printed objects a smooth surface structure, while KG provided MP with sufficient mechanical strength (proper G' and load bearing capacity) to be capable of self-supporting.

Influence of different functional ingredients on physical properties, rheology, tribology, and oral perceptions of no fat stirred yoghurt.

Effects of adding four functional ingredients: inulin, pectin, galacto-oligosaccharides (GOS), and beta glucan on physical, rheology, tribology, and sensory characteristics of skim (0.1% fat) stirred yoghurt were studied. Three levels of each ingredient were chosen: inulin (7, 8, and 9%), pectin (0.2, 0.25, and 0.3%), GOS (9.1, 11.3, and 13.6%), and beta glucan (0.1, 0.2, and 0.3%). Among the investigated ingredients, inulin and GOS appeared to be preferable choices due to their ability to both reduce syneresis and slightly increase sample lubrication while maintaining texture, rheology, and sensory characteristics of skim yoghurt. Pectin and beta glucan, conversely, increased viscosity and gel strength, slightly increased sample lubrication for the skim yoghurt but created large particles (i.e., greater than 100 µm) in the product body. This led to the increase in lumpiness and residual coating while reducing smoothness and creaminess of the sample. The observed tribology behaviors of the stirred yoghurts were similar to the previous study of pot-set yoghurt whose friction curves comprised four friction zones (Nguyen, Kravchuk, Bhandari, and Prakash). The sensory characteristics of six selected samples for various texture and mouthfeel attributes obtained from a trained panel were in agreement with particle size, rheology, and tribology characteristics of the yoghurt samples. PRACTICAL APPLICATIONS: With the increasing demand for low fat and functional food, there is a need to understand the impact of adding functional ingredients in low fat yoghurt to satisfy consumers' requirements. This study investigates the effects of these functional ingredients at different dosages on physical, rheology, tribology, and sensory characteristics of skim (0.1% fat) stirred yoghurt. The results from this study may guide use of functional ingredients in yoghurt production.

Crystallization and melting properties of mixtures of milk fat stearin and omega-3 rich oils.

Solid milk fat stearin (S25) can be a promising oxidation retarder due to its capacity to entrap liquid oils, especially for incorporating omega-3 (ω-3) rich oils into dairy products. Thermal properties of S25/ω-3 rich oil mixtures are necessary for such application. The effects of S25 on the crystallization and melting behaviours of ω-3 rich oils, namely fish oil (FO), linseed oil (LO) and krill oil (KO), were investigated by differential scanning calorimetry (DSC). Thermograms showed that with S25 concentration increasing, transitions of FO and LO shifted to lower and largely to higher temperatures, respectively, while crystallization temperature of KO slightly decreased. Negative, positive and low values of interaction enthalpy (ΔHint) suggested the adverse, beneficial and limited effect of S25 on the crystallization of S25/FO, S25/LO and S25/KO mixtures, respectively. LO could have the best oxidative stability upon the addition of S25 since their interactions facilitated earlier and stronger crystallization.

Encapsulation of tea tree oil by amorphous beta-cyclodextrin powder.

An innovative method to encapsulate tea tree oil (TTO) by direct complexation with solid amorphous beta-cyclodextrin (ß-CD) was investigated. A ß-CD to TTO ratio of 90.5:9.5 (104.9mg TTO/g ß-CD) was used in all complexation methods. The encapsulation was performed by direct mixing, and direct mixing was followed by the addition of water (13-17% moisture content, MC) or absolute ethanol (1:1, 1:2, 1:3 and 1:4 TTO:ethanol). The direct mixing method complexed the lowest amount of TTO (60.77mg TTO/g ß-CD). Powder recrystallized using 17% MC included 99.63mg of TTO/g ß-CD. The addition of ethanol at 1:2 and 1:3 TTO:ethanol ratios resulted in the inclusion of 94.3 and 98.45mg of TTO/g ß-CD respectively, which was similar to that of TTO encapsulated in the conventional paste method (95.56mg TTO/g ß-CD), suggesting an effective solid encapsulation method. The XRD and DSC results indicated that the amorphous TTO-ß-CD complex was crystallized by the addition of water and ethanol.

Repellent effects of Melaleuca alternifolia (tea tree) oil against cattle tick larvae (Rhipicephalus australis) when formulated as emulsions and in ß-cyclodextrin inclusion complexes.

Rhipicephalus australis (formerly Boophilus microplus) is a one host tick responsible for major economic loss in tropical and subtropical cattle production enterprises. Control is largely dependent on the application of acaricides but resistance has developed to most currently registered chemical groups. Repellent compounds that prevent initial attachment of tick larvae offer a potential alternative to control with chemical toxicants. The repellent effects of Melaleuca alternifolia oil (TTO) emulsions and two ß-cyclodextrin complex formulations, a slow release form (SR) and a modified faster release form (FR), were examined in a series of laboratory studies. Emulsions containing 4% and 5% TTO applied to cattle hair in laboratory studies completely repelled ascending tick larvae for 24h whereas 2% and 3% formulations provided 80% protection. At 48h, 5% TTO provided 78% repellency but lower concentrations repelled less than 60% of larvae. In a study conducted over 15 days, 3% TTO emulsion applied to cattle hair provided close to 100% repellency for 2 days, but then protection fell to 23% by day 15. The FR formulation gave significantly greater repellency than the emulsion and the SR formulation from day 3 until the end of the study (P<0.05), providing almost complete repellency at day 3 (99.5%), then decreasing over the period of the study to 49% repellency at day 15. Proof of concept is established for the use of appropriately designed controlled-release formulations to extend the period of repellency provided by TTO against R. australis larvae.