Nanoencapsulation of Oliveria decumbens Vent./basil essential oils into gum arabic/maltodextrin: Improved in vitro bioaccessibility and minced beef meat safety.

This study investigated the functional properties of freeze-dried encapsulated Oliveria decumbens Vent. (OEO) and basil (BEO) essential oils (EOs) in maltodextrin/gum arabic coating solution (1:1). Nanoencapsulated EOs were evaluated in terms of size, polydispersity, encapsulation efficiency, morphology, antioxidant, and antibacterial activities (AOA and ABA), and sensory characteristics in vitro compared to the control. The TPC (30.43 to 32.41 mg GAE/g DW) and AOA (25.97 to 26.42 %) were determined in free and encapsulated OEO, and ABA was observed, which were higher than BEO. Both free and encapsulated OEO and BEO demonstrated significant ABA against various Gram-positive and Gram-negative bacteria, with MIC values ranging from 0.25 to 1.25 mg/mL and MBC values ranging from 1.00 to 3.00 mg/mL. In minced meat, both free and encapsulated oils effectively reduced bacterial counts during refrigerated storage, with log reductions ranging from 1.00 to 6.48 CFU/g. Additionally, the pH and thiobarbituric acid values in meat samples were better maintained with the addition of oils. Sensory analysis showed that the encapsulated oils effectively masked their natural flavor and aroma, making them suitable for incorporation into food. Finally, OEO and BEO nanocapsules can improve the standard and safety of meat products due to their antioxidant and antibacterial properties.

Assessing Impact of Cooking Methods on the Physicochemical and Sensory Properties of Instant Fortified Rice Congee for the Elderly.

Instant rice congee (IRC) fortified with functional ingredients is designed for supplementation in nourishing the elderly. In this study, collagen peptide and curcumin were fortified in IRC to improve antioxidant and protein content. Different cooking methods were used to prepare rice congee in order to retain the nutritional content of instant fortified rice congee (IFRC). The effect of cooking methods on IFRC were investigated in this study using field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). As for cooking methods, the steaming method (IFRC-S) exhibited the highest total phenolic content (TPC) at 36.13 ± 5.63 mg GAE/g sample; a ferric reducing antioxidant power (FRAP) value of 6.39 ± 0.24 mg TE/g sample and protein content at 52.20 ± 6.48%. There were no significant differences (p > 0.05) in the texture analysis of hardness, cohesiveness and viscosity between the different cooking methods. However, the boiling method (IFRC-B) showed the highest adhesiveness, at -58.78 ± 11.55 g/s. IFRC with different cooking methods also had no significant differences (p > 0.05) in bulk density, volume expansion and the water absorption index. In sensory analysis, it was found that there were no significant differences (p > 0.05) detected in attribute colour, odour, taste, texture and overall acceptability between each cooking method. This study is particularly useful for gaining a preliminary understanding of the development of IRC focused on the elderly.

Separation of Chromium (VI), Copper and Zinc: Chemistry of Transport of Metal Ions across Supported Liquid Membrane.

Prior to applying supported liquid membranes (SLM) with strip dispersion for separation of chromium (VI), copper and zinc, suitable chemical settings were determined through solvent extraction and stripping studies. More than 90% of copper and zinc could be simultaneously extracted with at least 3% (v/v) di-(2-ethylhexyl)phosphoric acid (D2EHPA) at a feed equilibrium pH in the range of 3.5-5.0. For stripping, theoretical model equations derived and experimental results revealed that suitable concentrations of lower acid strength reagents can strip metals that have weaker metal-extractant bond without significantly stripping metals that have a stronger metal-extractant bond. Therefore, in a setup comprising three compartments separated by two SLM, we propose to fill the three compartments in the following order: feed-strip dispersion containing low acid strength reagent-strong acid. An organic phase with 4% (v/v) D2EHPA was used. From stripping experiments, 0.2 mol/L pH 3 citrate buffer, which resulted in the highest copper recovery (88.8%) and solution purity (99.0%), was employed as the low acid strength reagent while the strong acid consisted of 1 mol/L sulfuric acid. In 26 h, 99.1% copper was recovered by citrate buffer with 99.8% purity and 95.1% zinc was recovered by sulfuric acid with 98.4% purity. Chromium (VI), copper and zinc could be separated effectively using this separation strategy.

Influence of low-level gelling agents on the dissolution and in-vitro nutrient release study of coconut water-based hydrogel.

The purpose of this study was to evaluate the controlled-release properties of nutrients from coconut water-based hydrogel. Hydrogels were prepared at varying proportions of gellan and xanthan gums such that the total weight of the gelling agents for all 11 formulations was 1% (w/w) in coconut water. The formulation of the hydrogel was selected using gravimetric analysis by evaluating the dissolution weight of the hydrogel in simulated gastric fluid and simulated intestinal fluid. Interestingly, hydrogel with 0.7% gellan gum and 0.3% xanthan gum showed the most tolerance towards simulated gastric and intestinal fluids over a 1-h period. The in-vitro release study was performed in simulated gastric fluid and followed by simulated intestinal fluid for about 2 h. The trend of release profile showed that the hydrogel had the ability to sustain the nutrients release over a period of 1 h. After 75 min, the release trend was static indicated the nutrients was released from the hydrogel. In conclusion, a coconut water-based hydrogel formulated with 0.7% of gellan and 0.3% of xanthan gum has demonstrated its controlled-release property as evidenced by its effectiveness in the sustained release of nutrients over a period of 1 h.

Detecting adulteration of stingless bee honey using untargeted 1H NMR metabolomics with chemometrics.

As stingless bee honey (SBH) is gaining in popularity in the Malaysian market, it is now prone to adulteration. The higher price of SBH compared to floral honey has led to the use of unusual adulterants such as vinegar and even floral honey to mimic the unique taste and appearance of SBH. Since the current AOAC 998.12 method fails to detect these adulterants as their δ13C values are in the range for C3 plants, untargeted 1H NMR metabolomics was proposed. Principal component analysis of SBH 1H NMR fingerprints was able to distinguish authentic SBHs from adulterated ones down to 1% adulteration level for selected adulterants. Discriminant analysis showed promising results in distinguishing the preliminary datasets of authentic SBHs from the adulterated ones, including discriminating SBHs adulterated with different adulterants derived from C3 and C4 plants. Hence, to assure any emerging adulterant can be detected, all 1H NMR regions should be considered.

Optimization of soy protein isolate, microbial transglutaminase and glucono-δ-lactone in gluten-free rice noodles.

BACKGROUND: Rice flour does not contain gluten and lacks cohesion and extensibility, which is responsible for the poor texture of rice noodles. Different technologies have been used to mitigate this challenge, including hydrothermal treatments of rice flour, direct addition of protein in noodles, use of additives such as hydrocolloids and alginates, and microbial transglutaminase (MTG). Recently, the inclusion of soy protein isolate (SPI), MTG, and glucono-δ-lactone (GDL) in the rice noodles system yielded rice noodles with improved texture and more compact microstructure, hence the need to optimize the addition of SPI, MTG, and GDL to make quality rice noodles. RESULTS: Numerical optimization showed that rice noodles prepared with SPI, 68.32 (g kg-1 of rice flour), MTG, 5.06 (g kg-1 of rice flour) and GDL, 5.0 (g kg-1 of rice flour) gave the best response variables; hardness (53.19 N), springiness (0.76), chewiness (20.28 J), tensile strength (60.35 kPa), and cooking time (5.15 min). The pH, sensory, and microstructure results showed that the optimized rice noodles had a more compact microstructure with fewer hollows, optimum pH for MTG action, and overall sensory panelists also showed the highest preference for the optimized formulation, compared to other samples selected from the numerical optimization and desirability tests. CONCLUSION: Optimization of the levels of SPI, MTG, and GDL yielded quality noodles with improved textural, mechanical, sensory, and microstructural properties. This was partly due to the favourable pH value of the optimized noodles that provided the most suitable conditions for MTG crosslinking and balanced electrostatic interaction of proteins. © 2020 Society of Chemical Industry.

Effects of honey types and heating treatment on the textural, thermal, microstructural, and chemical properties of glutinous rice flour gels.

Hardening issue in starch-based products that arises during storage, is ascribed to the long-term starch retrogradation which involves the recrystallisation of amylopectin. Present study aimed to delay storage hardening with the addition of high diastase honey bee honey (HBH) and low diastase kelulut bee honey (KBH) into glutinous rice flour (GRF) gels. As compared to KBH, retardation of texture deterioration by HBH was more prominent as evidenced by the significantly (p < .05) lowest hardness and rate of hardening of GRF gel added with HBH (honeygel) throughout the 7-day storage. Heated honey and sugar solution did not reduce gel hardness that gel weakening was associated to the naturally occurring diastase in raw honey. Hence, only conventional GRF gel (congel), GRF gel added with KBH (kelugel) and honeygel were assessed for intrinsic viscosity, thermal, microstructural and chemical properties. The results were substantiated by the significantly (p < .05) lowest intrinsic viscosity (62.93 mL/g) and thermal enthalpy (333.7 J/g) of honeygel. A weak gel network structure was illustrated in honeygel with the significantly (p < .05) highest pore diameter (125.27 µm). In conclusion, the GRF gel has successfully demonstrated the potential of honey diastase in inhibiting the long-term retrogradation which could solve the industrial real problem.

Influence of honey types and heating treatment on the rheological properties of glutinous rice flour gels.

Present study compared the rheological properties of glutinous rice flour (GRF) gel (33.3%, w/v) added with raw bee honey (RBH) or stingless bee honey (SBH) with/without heating treatment. RBH (diatase activity: 12.14 Schade) and SBH (1.53 Schade) significantly reduced the network of GRF gel by lowering the gel viscosity, with RBH having the highest rate of viscosity decrease (- 2.74 × 10-5 Pa). As the addition of heated-SBH or heated-RBH did not reduce gel viscosity, it was hypothesised that active diastase played a major role to weaken gel network. This was further supported by the significant and the lowest storage modulus (G') value of RBH-GRF gel (5.99 ± 0.02 Pa), as compared to SBH-GRF (6.27 ± 0.04 Pa) and control (6.33 ± 0.04 Pa). A detail of rheological behaviour of the gels was further explained using power law. Overall, this GRF gel model has successfully demonstrated the potential of honey diastase in weakening network of starch-based food.

Variation of δ2H, δ18O & δ13C in crude palm oil from different regions in Malaysia: Potential of stable isotope signatures as a key traceability parameter.

A total of 33 crude palm oil samples were randomly collected from different regions in Malaysia. Stable carbon isotopic composition (δ13C) was determined using Flash 2000 elemental analyzer while hydrogen and oxygen isotopic compositions (δ2H and δ18O) were analyzed by Thermo Finnigan TC/EA, wherein both instruments were coupled to an isotope ratio mass spectrometer. The bulk δ2H, δ18O and δ13C of the samples were analyzed by Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA) and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). Unsupervised HCA and PCA methods have demonstrated that crude palm oil samples were grouped into clusters according to respective state. A predictive model was constructed by supervised OPLS-DA with good predictive power of 52.60%. Robustness of the predictive model was validated with overall accuracy of 71.43%. Blind test samples were correctly assigned to their respective cluster except for samples from southern region. δ18O was proposed as the promising discriminatory marker for discerning crude palm oil samples obtained from different regions. Stable isotopes profile was proven to be useful for origin traceability of crude palm oil samples at a narrower geographical area, i.e. based on regions in Malaysia. Predictive power and accuracy of the predictive model was expected to improve with the increase in sample size. Conclusively, the results in this study has fulfilled the main objective of this work where the simple approach of combining stable isotope analysis with chemometrics can be used to discriminate crude palm oil samples obtained from different regions in Malaysia. Overall, this study shows the feasibility of this approach to be used as a traceability assessment of crude palm oils.