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关键词： Composition   Enzymatic inactivation kinetics   Wax apple juice   Physicochemical properties   Polyphenol oxidase  

摘要： Thermal treatment can reduce the microbial load and enzymatic activity, which is important to produce a safe and good quality product in the fruit juice industry. Hence, it is crucial to determine suitable thermal processing condition parameters based on the composition and thermal properties of enzymes present in fruit juice to avoid over-processing. The aim of this work was to determine the enzymatic inactivation kinetics of wax apple to obtain useful information for production of ready-to-drink wax apple juice. The wax apple juice prepared in the present study complied with Malaysia Food Regulations 1985 Regulation 235. The main sugars present in the wax apple juice are fructose and glucose, and traces of sucrose. High content of potassium was detected in the wax apple juice. In addition, wax apple juice contains a considerable amount of phenolic compounds. The thermal inactivation kinetics of polyphenol oxidase (PPO) followed the first order kinetic model. The activation energy, enthalpy changes, D-88.4 degrees C, and z value of PPO obtained were 75.93 kJ/mol, 62.14 kJ/mol, 5.89 min, and 36.9 degrees C, respectively. In conclusion, the results evidenced that PPO which is more heat resistant than peroxidase, is a better enzyme inactivation indicator for the thermal treatment of wax apple juice. Therefore, PPO could be used as a heat treatment index for thermal processing that would be useful in designing thermal process for manufacturing of ready-to-drink wax apple juice.

关键词： Adhesion   Chitosan   Enzymatic degradation   Hybrid layer   Microtensile bond strength  

摘要： This study evaluated the physicochemical characteristics (particle size, zeta potential and polydispersity index) of a universal adhesive system (Scotchbond Universal/3 M ESPE) containing 0.5% chitosan (Ch), used as a self etching (SE) or a total-etching (TE) strategy, and the effects of this chitosan-incorporated adhesive on micro tensile bond strength stability to dentin, dentin-restoration interface, and gelatinolytic activity by in situ zymography. Dentin surfaces received treatments applying adhesive systems with or without Ch, and were used with an SE or a TE strategy. Composite resin blocks were built, and sticks were obtained and separated for microtensile bond strength tests (n = 10). Assessments were made after 24-h and 6-month storage, and the dentin/resin interface was evaluated by scanning electron microscopy (SEM) and zymography analyses (n = 4). Particle size and polydispersity index increased significantly, whereas zeta potential increased and decreased significantly over time. Microtensile bond strength for the SE (without Ch) and TE (with Ch) strategies decreased significantly after 6 months (p < 0.0001). At 6 months, the TE strategy had significantly higher microtensile bond strength than SE. SE and TE strategies (both with Ch) provided higher collagenolytic activity than SE and TE (without Ch) (p = 0.0007). Addition of 0.5% chitosan promoted solution instability. Both the TE strategy and the Ch incorporation affected microtensile bond strength negatively. There was higher collagenolytic activity when Ch was incorporated into the adhesive, regardless of the application strategy.

关键词： Breadsticks   estimated glycaemic index   flour substitution   physicochemical properties   resistant starch   sensory characteristics  

摘要： This study determined the physicochemical, sensorial and nutritional properties of breadsticks to which a resistant starch (RS)-rich ingredient was incorporated by partial substitution, that is, 40%-70%, of hard wheat flour in the control recipe. Wheat flour substitution at the levels exceeding 50% lightened the colour while decreasing the moisture content and hardness of breadsticks, which was explainable by the microstructure. Changes in properties of breadsticks also affected the suitability of its sensory attributes, particularly colour and texture. Breadsticks, of which half of wheat flour was substituted, contained less protein and calories but higher carbohydrate than the control formula. Such flour substitution increased RS content closed to its effective dose of 15 g in a 45-g serving, which led to approximately 15% reduction inin vitroglycaemic index. Therefore, incorporating effective dose of RS in breadsticks could be performed, without causing substantial changes in product quality, by partial substitution of wheat flour.

关键词： Physicochemical properties  

摘要： The aim of this study was to obtain and characterize a lyophilized leaf powder from Acmella oleracea (LPA) as a functional food ingredient. Sorption isotherms of LPA display a monolayer moisture content of 9.1 and 9.3 g H2O 100 g(-1) for adsorption and desorption, respectively. The flavonoids, ascorbic acid, and total polyphenols content, were approximately 235 mg 100 g(-1), 18 mg 100 g(-1), and 2,480 mg GAE 100 g(-1), respectively. The antioxidant activity by TEAC showed the greatest value, similar to 291 mg TE L-1, against DPPH and FRAP assays (p < .05). The FTIR spectrum revealed high intensity bands at 3,400 cm(-1) related to vibrations of cellulose and organic acids. The thermo-behavior showed an initial degradation temperature at 222 degrees C and peak temperature of 278 degrees C. These results indicate great potential of LPA as a natural source of bioactive compounds, which could contribute to its utilization as a functional ingredient in foods. Practical applications The lyophilized leaf powder from Acmella oleracea as a natural source of bioactive compounds could contribute to its utilization as a functional ingredient in foods.

关键词： Cocrystals   Polyphenol   Bioavailability   Food-grade coformers  

摘要： Background: Polyphenols are an important group of bioactive compounds used as food ingredients and supplements. However, its application is limited because they have low water-solubility, bioavailability and stability in gastrointestinal fluids, aspects that can be modulated by polyphenols cocrystallization. Nevertheless, cocrystals have been mostly used in pharmaceutical field, with only few recent uses for food-related polyphenols. Scope and approach: cocrystallization is addressed as a powerful tool to modulate the properties of food-relevant polyphenols. As the first review concerning food related cocrystals, this review emphasizes cocrystals from foodgrade coformers, summarizing production routes, solvents used, and safety-related problems. Key findings and conclusions: Polyphenol-based cocrystals can be produced by slurry, liquid-assisted grinding and slow evaporation, and most recently by microwave assisted and supercritical solvent. The cocrystallization can modulate polyphenol properties such as dissolution, bioavailability, photoluminescence and tensile strength. The bioactivity can also be tuned, providing cocrystals with better antioxidant, antihemolytic, and anti-inflammatory properties. These combined attributes widespread the possible applications of these new materials.

关键词： Hemp seed oil   Liposome   Encapsulation efficiency   Polyphenols   Delta 9-tetrahydrocannabinol  

摘要： Hemp seed oil (HSO) liposomes (HSOLs) were prepared by ethanol injection-ultrasonic dispersion (EIUD). The encapsulation efficiency (EE) and oil loading ratio (OLR) were used as the response indicators to optimize the preparation conditions of the HSOLs. The average particle size (Z-Ave) of the prepared liposomes was 122 +/- 1.64 nm, the polydispersity index (PDI) was 0.21 +/- 0.06, the zeta potential (ZP) was-36.5 +/- 0.32 mV, the encapsulation efficiency (EE) was 81.3 +/- 1.62 % and the oil loading rate (LOR) was 6.13 +/- 0.07 %. Transmission electron microscopy (TEM) and cryo-scanning electron microscopy (cryo-SEM) showed that the morphology of the HSOLs was round, and the cut surface was regular. The storage and oxidative stability tests of the HSOLs showed that the Z-Ave was 152 +/- 1.87 nm and the polydispersity index (PDI) was 0.72 +/- 0.03 after storage for 70 days under natural light at 25 degrees C. The zeta potential change showed no trend. The polyphenolic content in the HSOLs was 2.25 mg GAE/100 g, the DPPH clearance rate was 60.7 %, and the Delta 9-tetrahydrocannabinol (Delta 9THC) content was 85.43 mg/kg.

关键词： Preferential vaporization   Droplet combustion   Multi-component   Surrogate fuel  

摘要： Isolated droplet burning behaviors of fuel mixtures that all share the fully pre-vaporized combustion behaviors of the same "global" Jet-A real fuel are investigated numerically to elucidate the effects of preferential vaporization. Predictions are generated using three such multi-component hydrocarbon mixtures (Mixture-1: n-decane/iso-octane/toluene 42.7/33.0/24.3, Mixture-2: n-dodecane/iso-octane/1,3,5 trimethyl benzene 49.0/21.0/30.0 and Mixture-3: n-hexadecane/iso-octane/1,3,5 trimethyl benzene 36.5/31.0/32.5 molar ratios), each having very different distillation properties. Simulations are performed using a transient onedimensional sphero-symmetric model, involving numerically reduced detailed chemical kinetics, and multicomponent gas-phase diffusive transport. The interactions among the different liquid-phase components are modeled using UNIFAC activity coefficient methodology. The predictions using Mixture-1 are found to be in good agreement with previously published drop-tower experiments for 550 mu m droplet combustion in air. Stagnant and internally mixed liquid-phase behaviors are both considered. Near fully mixed internal conditions and including sooting effects (observed in the experiments) result in predictions that are in good agreement with experimental drop diameter and flame-standoff ratio histories. By comparing predictions for the three mixtures, preferential vaporization effects exhibit strong non-linear dependences on initial droplet diameter and ambient pressure. At low pressures and for droplet sizes typical of those found in multi-phase gas turbine combustors, comparable diffusion and vaporization characteristic times favor frozen limit vaporization. However, at pressures typical of those found in applications, batch distillation dominates and preferential vaporization chemical property differences are found to become as significant as physical property effects in influencing combustion behaviors. (c) 2020 The Combustion Institute. Published

关键词： Whey protein isolate   Chitosan   Edible films   Complex coacervation  

摘要： The aim of this work was to study the potential application of edible films obtained by complex coacervation promoted by the electrostatic interactions between positively charged chitosan (CH) 3% (w/w) and negatively charged whey protein isolate (WPI) 3% (w/w). Preliminary assays of turbidimetry were made in order to find the optimal CH-to-WPI mass ratio for the complex coacervation. The maximum turbidity was obtained in the CH:WPI mass ratio of 0.1:1 (w/w). The dispersions of CH/WPI (both at 3% (w/w)), WPI 5% (w/w) and CH 3% (w/w) were analyzed by Cryo-scanning electron microscopy (Cryo-SEM) and the micrograph of CH/WPI coacervate presented a more compact network structure than dispersions of individual biopolymers. The composite CH/WPI films were prepared, characterized and their performance and physicochemical properties were compared with those of CH or WPI films, in terms of water vapor permeability (WVP), mechanical properties, solubility, sorption isotherms, optical properties, scanning electron microscopy (SEM) imaging, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Results revealed that the incorporation of small amounts of CH in the matrix of WPI led to form a composite film with higher tensile strength, lower deformation, malleability, flexibility, solubility and WVP in comparison to the mono-component WPI and CH films. The CH incorporation resulted in a decrease in equilibrium moisture content of the CH/WPI film and the GuggenheimAnderson-de Boer (GAB) model of sorption data indicated isotherms of type II. All the films presented a homogeneous structure, color transparency, which is desired in food applications and packaging technology.

关键词： Barley soluble fiber   beta-Glucan   Structural characteristic   Viscosity  

摘要： Glucans of multiple architecture and bioactivities are widely distributed in cereals. In our previous study, the barley water-soluble fiber (BSF) has been proved to possess hypoglycaemic and hypolipidaemic effects. A further attempt in the present study is to comprehensively demonstrate the structures and solution properties of main constituents in BSF. Two mainly homogeneous fractions (BSF-20 and BSF-80r) were purified from BSF, and their physicochemical and structural characterization were investigated. Methylation and 1D/2D NMR experiments indicated that BSF-20 was a linear beta-glucan, composed of beta-D-Glcp residues via (1 -> 4)-linkages, and occa- sionally single (1 -> 3)-linkage. The high performance size-exclusion chromatography coupled with multiangle laser light scattering, X-ray diffraction, rheological measurements and scanning electron microscopy were further conducted to analyze its solution property and morphology. BSF-20 adopted a linear flexible chain in aqueous solution, and exhibited high viscosity and strong gelling properties. Intertwined fibrous filaments were visualized by SEM observation. Besides, BSF-80r was a limit dextrin, which was an artefact caused by the incomplete hydrolysis of starch during the isolation of barley soluble fiber. Therefore, the highly viscous beta-glucan is the main biomacromolecule occurring in BSF. This work lays the groundwork for the potential application of barley soluble fiber in beverages and other liquid products as new thickeners and stabilizers.

关键词： Herbal teas   Brand name   Physicochemical parameters   Volatile compounds   Discrimination   Chemometrics  

摘要： In the present study, different herbal teas (anti-stress, mountain, sage, and chamomile), commercially available, were subjected to physicochemical and volatile compounds analyses to find the key descriptors that could characterize each product according to brand name using chemometrics. Multivariate analysis of variance showed significant differences (p < 0.05) for the herbal teas of a different type in relation to pH, electrical conductivity, total dissolved solids, salinity, colour and the volatile compounds (aldehydes, terpenoids/terpene ketones, hydrocarbons, esters, and furans). The implementation of linear discriminant analysis resulted in the perfect classification of herbal teas indicating those specific physicochemical and odorous descriptors for each type that could support products' brand name and uniqueness in the market and set the basis for the development of a novel packaging label in these products, concerning their physicochemical composition.