Migration studies of chemicals from contact materials have been widely conducted due to their importance in determining the safety and shelf life of a food product in their packages. The US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) require this safety assessment for food contact materials. So, migration experiments are theoretically designed and experimentally conducted to obtain data that can be used to assess the kinetics of chemical release. In this work, a parameter estimation approach was used to review and to determine the mass transfer partition and diffusion coefficients governing the migration process of eight antioxidants from poly(lactic acid), PLA, based films into water/ethanol solutions at temperatures between 20 and 50°C. Scaled sensitivity coefficients were calculated to assess simultaneously estimation of a number of mass transfer parameters. An optimal experimental design approach was performed to show the importance of properly designing a migration experiment. Additional parameters also provide better insights on migration of the antioxidants. For example, the partition coefficients could be better estimated using data from the early part of the experiment instead at the end. Experiments could be conducted for shorter periods of time saving time and resources. Diffusion coefficients of the eight antioxidants from PLA films were between 0.2 and 19×10-14m2/s at ~40°C. The use of parameter estimation approach provided additional and useful insights about the migration of antioxidants from PLA films.
Medium-and-Long Chain Triacylglycerol (MLCT) is a type of structured lipid that is made up of medium chain, MCFA (C8-C12) and long chain, LCFA (C16-C22) fatty acid. Studies claimed that consumption of MLCT has the potential in reducing visceral fat accumulation as compared to long chain triacylglycerol, LCT. This is mainly attributed to the rapid metabolism of MCFA as compared to LCFA. Our study was designed to compare the anti-obesity effects of a enzymatically interesterified MLCT (E-MLCT) with physical blend of palm kernel and palm oil (B-PKOPO) having similar fatty acid composition and a commercial MLCT (C-MLCT) made of rapeseed/soybean oil on Diet Induced Obesity (DIO) C57BL/6J mice for a period of four months in low fat, LF (7%) and high fat, HF (30%) diet. The main aim was to determine if the anti-obesity effect of MLCT was contributed solely by its triacylglycerol structure alone or its fatty acid composition or both. Out of the three types of MLCT, mice fed with Low Fat, LF (7%) E-MLCT had significantly (P<0.05) lower body weight gain (by ~30%), body fat accumulation (by ~37%) and hormone leptin level as compared to both the LF B-PKOPO and LF C-MLCT. Histological examination further revealed that dietary intake of E-MLCT inhibited hepatic lipid accumulation. Besides, analysis of serum profile also demonstrated that consumption of E-MLCT was better in regulating blood glucose compared to B-PKOPO and C-MLCT. Nevertheless, both B-PKO-PO and E-MLCT which contained higher level of myristic acid was found to be hypercholesterolemic compared to C-MLCT. In summary, our finding showed that triacylglycerol structure, fatty acid composition and fat dosage play a pivotal role in regulating visceral fat accumulation. Consumption of E-MLCT in low fat diet led to a significantly lesser body fat accumulation. It was postulated that the MLM/MLL/LMM/MML/LLM types of triacylglycerol and C8-C12 medium chain fatty acids were the main factors that contributed to the visceral fat suppressing effect of MLCT. Despite being able to reduce body fat, the so called healthful functional oil E-MLCT when taken in high amount do resulted in fat accumulation. In summary, E-MLCT when taken in moderation can be used to manage obesity issue. However, consumption of E-MLCT may lead to higher total cholesterol and LDL level.
The aim of this study was to develop formulations to produce lycopene nanodispersions and to investigate the effects of the homogenization pressure on the physicochemical properties of the lycopene nanodispersion. The samples were prepared by using emulsification-evaporation technique. The best formulation was achieved by dispersing an organic phase (0.3% w/v lycopene dissolved in dichloromethane) in an aqueous phase (0.3% w/v Tween 20 dissolved in deionized water) at a ratio of 1:9 by using homogenization process. The increased level of homogenization pressure to 500bar reduced the particle size and lycopene concentration significantly (p<0.05). Excessive homogenization pressure (700-900bar) resulted in large particle sizes with high dispersibility. The zeta potential and turbidity of the lycopene nanodispersion were significantly influenced by the homogenization pressure. The results from this study provided useful information for producing small-sized lycopene nanodispersions with a narrow PDI and good stability for application in beverage products.
Monoglycerides (MGs) and phytosterols (PS) are known to form firm oleogels with liquid oil. However, the oleogels are prone to undergo polymorphic transition over time that lead to crystals' aggregation thus, compromises physical properties. Thus, we combined MGs with PS to control the crystallization and modify the morphology of the combination oleogels, as both components are reported to interact together. The oleogels were prepared at different ratio combinations and characterized in their rheological, thermal, morphology, and diffraction properties. The results showed that the 8:2 MGP:PS exhibited higher storage modulus (G') than the MGP mono-component. The combination oleogels exhibited effects on the crystallization and polymorphic transition. Consequently, the effects led to change in the morphology of the combination oleogels which was visualized using optical and electron microscope. The resultant effect on the morphology is associated with crystal defect. Due to observable crystals of MGP and PS, it is speculated that the combination oleogels formed a mixed crystal system. This was confirmed with diffraction analysis in which the corresponding peaks from MGP and PS were observed in the combination oleogels. However, the 8:2 oleogel exhibited additional peak at 35.41Å. Ultimately, the 8:2 was the optimum combination observed in our study. Interestingly, this combination is inspired by nature as sterols (phytosterols) are natural component of lipid membrane whilst MGP has properties similar to phospholipids. Hence, the results of our study not only beneficial for oil structuring, but also for the fields of biophysical and pharmaceutical.
Edible bird's nest (EBN) is an expensive animal bioproduct due to its reputation as a food and delicacy with diverse medicinal properties. One kilogram of EBN costs ~$6000 in China. EBN and its products are consumed in mostly Asian countries such as China, Hong Kong, Taiwan, Singapore, Malaysia, Indonesia, Vietnam and Thailand, making up almost 1/3 of world population. The rapid growth in EBN consumption has led to a big rise in the trade scale of its global market. Presently, various fake materials such as tremella fungus, pork skin, karaya gum, fish swimming bladder, jelly, agar, monosodium glutamate and egg white are used to adulterate EBNs for earning extra profits. Adulterated or fake EBN may be hazardous to the consumers. Thus, it is necessary to identify of the adulterants. Several sophisticated techniques based on genetics, immunochemistry, spectroscopy, chromatography and gel electrophoresis have been used for the detection of various types of adulterants in EBN. This article describes the recent advances in the authentication methods for EBN. Different genetic, immunochemical, spectroscopic and analytical methods such as genetics (DNA) based techniques, enzyme-linked immunosorbent assays, Fourier transform infrared and Raman spectroscopic techniques, and chromatographic and gel electrophoretic methods have been discussed. Besides, significance of the reported methods that might pertain them to applications in EBN industry has been described. Finally, efforts have been made to discuss the challenges and future perspectives of the authentication methods for EBN.
Edible seaweeds are a good source of antioxidants, dietary fibers, essential amino acids, vitamins, phytochemicals, polyunsaturated fatty acids, and minerals. Many studies have evaluated the gelling, thickening and therapeutic properties of seaweeds when they are used individually. This review gives an overview on the nutritional, textural, sensorial, and health-related properties of food products enriched with seaweeds and seaweed extracts. The effect of seaweed incorporation on properties of meat, fish, bakery, and other food products were highlighted in depth. Moreover, the positive effects of foods enriched with seaweeds and seaweed extracts on different lifestyle diseases such as obesity, dyslipidemia, hypertension, and diabetes were also discussed. The results of the studies demonstrated that the addition of seaweeds, in powder or extract form, can improve the nutritional and textural properties of food products. Additionally, low-fat products with less calories and less saturated fatty acids can be prepared using seaweeds. Moreover, the addition of seaweeds also affected the health properties of food products. The results of these studies demonstrated that the health value, shelf-life and overall quality of foods can be improved through the addition of either seaweeds or seaweed extracts.
Two Malaysian brown seaweeds, Sargassum siliquosum and Sargassum polycystum were first extracted using methanol to get the crude extract (CE) and further fractionated to obtain fucoxanthin-rich fraction (FRF). Samples were evaluated for their phenolic, flavonoid, and fucoxanthin contents, as well as their inhibitory activities towards low density lipoprotein (LDL) oxidation, angiotensin converting enzyme (ACE), α-amylase, and α-glucosidase. In LDL oxidation assay, an increasing trend in antioxidant activity was observed as the concentration of FRF (0.04-0.2mg/mL) and CE (0.2-1.0mg/mL) increased, though not statistically significant. As for serum oxidation assay, significant decrease in antioxidant activity was observed as concentration of FRF increased, while CE showed no significant difference in inhibitory activity across the concentrations used. The IC50 values for ACE inhibitory activity of CE (0.03-0.42mg/mL) were lower than that of FRF (0.94-1.53mg/mL). When compared to reference drug Voglibose (IC50 value of 0.61mg/mL) in the effectiveness in inhibiting α-amylase, CE (0.58mg/mL) gave significantly lower IC50 values while FRF (0.68-0.71mg/mL) had significantly higher IC50 values. The α-glucosidase inhibitory activity of CE (IC50 value of 0.57-0.69mg/mL) and FRF (IC50 value of 0.50-0.53mg/mL) were comparable to that of reference drug (IC50 value of 0.54mg/mL). Results had shown the potential of S. siliquosum and S. polycystum in reducing cardiovascular diseases related risk factors following their inhibitory activities on ACE, α-amylase and α-glucosidase. In addition, it is likelihood that FRF possessed antioxidant activity at low concentration level.
The rheological properties, microstructure, textural properties, colour and droplet size distribution of mayonnaise-like emulsion models prepared using 10-30wt.% of palm olein-based diacylglycerol (POL-DAG) oil were compared with those of the control (100wt.% VCO) model. There were significant (P<0.05) differences in the particle size distribution of the oil droplets, the textural properties, and the rheological properties of the various emulsion models. The rheological analysis included the determination of the flow curves, yield stress, thixotropy, apparent viscosity, and viscoelastic parameters. The concentrated oil-in-water (O/W) emulsion with 30wt.% POL-DAG substitution exhibited high thixotropy. The POL-DAG content had a substantial effect on the rheological properties of yield stress, storage modulus (G') and loss modulus (G″). The pseudoplastic behaviour of the emulsions was demonstrated. The size of the particles in the 30% POL-DAG-substituted emulsion was dramatically increased after one day and 30days of storage. All of the emulsion samples with POL-DAG substituted for VCO showed a relatively non-uniform bimodal droplet size distribution after one day of storage. In general, substitution of 10-20wt.% POL-DAG oil is appropriate for preparing O/W emulsions that had flow curves and textural properties similar to those of the control sample.
Extract from papaya leaves, a waste material from fruit farms in Malaysia was previously reported to possess remarkable antioxidative activities. In this study, papaya leaf extract was separated into fractions of different polarities [petroleum ether (PE), ethyl acetate (EA), n-butanol (NB) and water (W) fractions]. The aim of this research was to determine the most active fraction in terms of its chemopreventive effects towards oxidative stress and the chemical constituents involved. The cytoprotective nature of the papaya fractions was observed against t-BOOH-induced oxidative stress on HepG2 liver cell line. ROS assay indicated that only PE and EA effectively reduced the increment of radical due to the pro-oxidant, t-BOOH. Nevertheless, PE was a stronger ROS scavenger by demonstrating ROS reducing activity in a dose-dependent manner to the basal level. This fraction was also found to inhibit cell death caused by t-BOOH toxicity, attenuating lactate dehydrogenase enzyme leakage by more than 90% (p<0.05). In addition, gene expression of phase II antioxidant enzymes (hmox-1 and nqo-1) and their transcription factor (nrf-2) were shown to be upregulated upon PE treatment during a time-course study. A GC-MS fingerprint of the active fraction was subsequently obtained with standardization using the marker compound; α-tocopherol, a well known antioxidant. However, this pure compound was not as effective as its corresponding PE concentrations in ROS reduction. Hence, PE of papaya leaf extract was a strong antioxidant and cytoprotectant with tremendous potential to be harnessed into the next therapeutic remedy against oxidative stress of the liver.