Fragaria chiloensis fruit has a short postharvest life mainly due to its rapid softening. In order to improve its postharvest life, preharvest applications of methyl jasmonate (MeJA) and chitosan were evaluated during postharvest storage at room temperature. The quality and chemical parameters, and protection against decay were evaluated at 0, 24, 48 and 72 h of storage from fruits of two subsequent picks (termed as first harvest and second harvest). In general, fruits treated with MeJA and chitosan maintained higher levels of fruit firmness, anthocyanin, and showed significant delays in decay incidence compared to control fruit. MeJA-treated fruits exhibited a greater lignin content and SSC/TA ratio, and delayed decay incidences. Instead, chitosan-treated fruits presented higher antioxidant capacity and total phenol content. In short, both the elicitors were able to increase the shelf life of fruits as evidenced by the increased levels of lignin and anthocyanin, especially of the second harvest.
Antioxidant and α-amylase inhibitor peptides were successfully extracted from Pinto bean protein isolate (PBPI) using Protamex. A factorial design experiment was conducted and the effects of extraction time, pH and temperature were studied. pH 7.5, extraction time of 1h, S/E ratio of 10 (w/w) and temperature of 50 °C gave the highest antioxidant activities (i.e., ABTS scavenging activity (53.3%) and FRAP value (3.71 mM)), whereas pH 6.5 with the same extraction time, S/E ratio and temperature, gave the highest α-amylase inhibitory activity (57.5%). It was then fractioned using membrane ultrafiltration with molecular weight cutoffs of 100, 50, 30, 10 and 3 kDa. Peptide fraction <3 kDa, which exhibited the highest antioxidant activities (i.e., ABTS (42.2%) and FRAP (0.81 mM)) and α-amylase inhibitory activity (62.1%), was then subjected to LCMS and MS/MS analyses. Six sequences were identified for antioxidant peptides, whereas seven peptides for α-amylase inhibitor.
This research was conducted to investigate the effects of different grinding techniques (dry, semi-wet and wet) of milled rice grains on the damaged starch and particle size distribution of flour produced from a new variety, MR263, specifically related to the pasting and thermal profiles. The results indicated that grinding techniques significantly (p<0.05) affected starch damage content and particle size distribution of rice flour. Wet grinding process yields flour with lowest percentage of starch damage (7.37%) and finest average particle size (8.52μm). Pasting and gelatinization temperature was found in the range of 84.45-89.63°C and 59.86-75.31°C, respectively. Dry ground flour attained the lowest pasting and gelatinization temperature as shown by the thermal and pasting profiles. Correlation analysis revealed that percentage of damaged starch granules had a significant, negative relationship with pasting temperature while average particle size distribution had a significant, strong negative relationship with gelatinization temperature.
The influence of fermentation temperatures (8°C, 16°C, and 32°C) and yeast levels (2%, 4%, and 6% of the flour) on the formation of volatile compounds in the crust of whole meal wheat bread was investigated. The fermentation times were regulated to optimum bread height for each treatment. The volatile compounds were extracted by dynamic headspace extraction and analyzed by gas chromatography-mass spectrometry. The results were evaluated using multivariate data analysis and ANOVA. In all crust samples 28 volatile compounds out of 58 compounds were identified and the other 30 compounds were tentatively identified. Higher fermentation temperatures promoted the formation of Maillard reaction products 3-methyl-1-butanol, pyrazine, 2-ethylpyrazine, 2-ethyl-3-methylpyrazine, 2-vinylpyrazine, 3-hydroxy-2-butanone, 3-(methylsulfanyl)-propanal, and 5-methyl-2-furancarboxaldehyde whereas at lower temperature (8°C) the formation of 2- and 3-methylbutanal was favored. Higher levels of yeast promoted the formation of 3-methyl-1-butanol, 2-methyl-1-propanol and 3-(methylsulfanyl)-propanal, whereas hexanal was promoted in the crust fermented with lower yeast level.
In present study aflatoxins (AFs) and ochratoxin A (OTA) were analysed in 208 samples of rice and products collected from central areas of Punjab, Pakistan. The analysis was carried out using HPLC equipped with fluorescence detector. The results have shown that 35% of the samples were found contaminated with AFs, out of which 19% and 24% samples were found to be above the European Union (EU) maximum content for AFB1 and total AFs, respectively. About 19% samples were found contaminated with OTA and 14% samples were found to be above the EU maximum content. The highest mean level of AFB1 and total AFs were found in brown rice samples i.e. 8.91 and 12.4μg/kg, respectively. However, white rice samples have shown the highest mean level of OTA (8.50μg/kg) with highest level of 24.9μg/kg. The high mean dietary exposure 22.2 and 24.2ngkg(-1)bwday(-1) to AFB1 and OTA, respectively poses significant health hazard for local population.
A new optosensor for visual quantitation of nitrite (NO2(-)) ion has been fabricated by physically immobilizing Safranine O (SO) reagent onto a self-adhesive poly(n-butyl acrylate) [poly(nBA)] microspheres matrix, which was synthesized via facile microemulsion UV lithography technique. Evaluation and optimization of the optical NO2(-) ion sensor was performed with a fiber optic reflectance spectrophotometer. Scanning electron micrograph showed well-shaped and smooth spherical morphology of the poly(nBA) microspheres with a narrow particles size distribution from 0.6μm up to 1.8μm. The uniform size distribution of the acrylic microspheres promoted homogeneity of the immobilized SO reagent molecules on the microspheres' surfaces, thereby enhanced the sensing response reproducibility (<5% RSD) with a linear range obtained from 10 to 100ppm NO2(-) ion. The micro-sized acrylic immobilization matrix demonstrated no significant barrier for diffusion of reactant and product, and served as a good solid state ion transport medium for reflectometric nitrite determination in food samples.
This paper reports on the extraction of Moringa oleifera (MO) oil by using aqueous enzymatic extraction (AEE) method. The effect of different process parameters on the oil recovery was discovered by using statistical optimization, besides the effect of selected parameters on the formation of its oil-in-water cream emulsions. Within the pre-determined ranges, the use of pH 4.5, moisture/kernel ratio of 8:1 (w/w), and 300stroke/min shaking speed at 40°C for 1h incubation time resulted in highest oil recovery of approximately 70% (goil/g solvent-extracted oil). These optimized parameters also result in a very thin emulsion layer, indicating minute amount of emulsion formed. Zero oil recovery with thick emulsion were observed when the used aqueous phase was re-utilized for another AEE process. The findings suggest that the critical selection of AEE parameters is key to high oil recovery with minimum emulsion formation thereby lowering the load on the de-emulsification step.
Pomegranate peel is a rich source of phenolic compounds (such as punicalagin and hydroxybenzoic acids). However, the content of such bioactive compounds in the peel extract can be affected by extraction type and condition. It was hypothesized that the optimization of a pulsed ultrasound-assisted extraction (PUAE) technique could result in the pomegranate peel extract with higher yield and antioxidant activity. The main goal was to optimize PUAE condition resulting in the highest yield and antioxidant activity as well as the highest contents of punicalagin and hydroxybenzoic acids. The operation at the intensity level of 105W/cm(2) and duty cycle of 50% for a short time (10min) had a high efficiency for extraction of phenolics from pomegranate peel. The application of such short extraction can save the energy and cost of the production. Punicalagin and ellagic acid were the most predominant phenolic compounds quantified in the pomegranate peel extract (PPE) from Malas variety. PPE contained a minor content of gallic acid.
Fucoidan is a sulphated polysaccharide that consists mainly of fucose, normally found in brown seaweeds. In this study, fucoidan was extracted from Sargassum binderi (Fsar) from Malaysia and subsequently characterised. The chemical characteristics of Fsar were found to be different than those of commercial food grade fucoidan (Fysk) and those of previously studied fucoidans. NMR analysis proposed that the main structure of Fsar is →3)fuc-2-OSO3(-)(1→3)fuc(1→. The molecular weight (47.87kDa) and degree of sulphation (0.20) of Fsar were higher than those of Fysk, at 27.98kDa and 0.15, respectively. However, Fsar's polydispersity index (1.12) and fucose content (34.50%) were lower than those of Fysk, at 1.88 and 43.30%, respectively. Both Fsar and Fysk showed similar thermo-gravimetric properties with four mass losses, amorphous in nature and negative optical rotations. Results show that Fsar has fundamental characteristics of fucoidan with different structural conformation i.e. variation in glycosidic linkages and sulphate group orientation.
The stability of lutein nanodispersions was evaluated during storage and when exposed to different environmental conditions. Lutein nanodispersions were prepared using Tween 80, sodium dodecyl sulfate (SDS), sodium caseinate (SC) and SDS-Tween 80 as the emulsifiers. During eight weeks of storage, all samples showed remarkable physical stability. However, only the SC-stabilized nanodispersion showed excellent chemical stability. Under different environmental conditions, the nanodispersions exhibited a varied degree of stability. All nanodispersions showed constant particle sizes at temperatures between 30 and 60°C. However, at pH 2-8, only the SC-stabilized nanodispersion was physically unstable. The addition of NaCl (300-400mM) only caused flocculation in nanodispersion stabilized by SDS-Tween 80. All nanodispersions were physically stable when subjected to different centrifugation speeds. Only Tween 80-stabilized nanodispersion was stable against the effect of freeze-thaw cycles (no phase separation observed). In this study, there was no particular emulsifier that was effective against all of the environmental conditions tested.
The purpose of this study was to identify porcine-specific peptide markers from thermally processed meat that could differentiate pork from beef, chevon and chicken meat. In the initial stage, markers from tryptic digested protein of chilled, boiled and autoclaved pork were identified using LC-QTOF-MS. An MRM method was then established for verification. A thorough investigation of LC-QTOF-MS data showed that only seven porcine-specific peptides were consistently detected. Among these peptides, two were derived from lactate dehydrogenase, one from creatine kinase, and four from serum albumin protein. However, MRM could only detect four peptides (EVTEFAK, LVVITAGAR, FVIER and TVLGNFAAFVQK) that were consistently present in pork samples. In conclusion, meat species determination through a tandem mass spectrometry platform shows high potential in providing scientifically valid and reliable results even at peptide level. Besides, the specificity and selectivity offered by the proteomics approach also provide a robust platform for Halal authentication.
The main objective of the present study was to investigate the effect of solvent type and ratio as well as the extraction techniques (i.e. supercritical fluid extraction (SFE) and conventional solvent extraction) on betacyanins and antioxidant activity of the peel and fresh extract from the red pitaya (Hylocereus polyrhizus). The peel and flesh extracts obtained by SFE at 25MPa pressure and 10% EtOH/water (v/v) mixture as a co-solvent contained 24.58 and 91.27mg/100ml total betacyanin, respectively; while the most desirable solvent extraction process resulted in a relatively higher total betacyanin in the peel and flesh extracts (28.44 and 120.28mg/100ml, respectively). The major betacyanins identified in the pitaya peel and flesh extracts were betanin, isobetanin, phyllocactin, butyrylbetanin, isophyllocactin and iso-butyrylbetanin. The flesh extract had the stronger antioxidant activity than the peel extract when the higher proportion of ethanol to water (E/W) was applied for the extraction.
The primary objective of this study was to evaluate the physicochemical and rheological properties of butter produced by Lactobacillus helveticus fermented cream. The incorporation of putative probiotic - the L. helveticus, to ferment cream prior to butter production was anticipated to alter the nutritional composition of butter. Changes in crude macronutrients and the resultant modification relating to textural properties of butter induced upon metabolic activities of L. helveticus in cream were focused in this research. Fermented butter (LH-butter) was produced by churning the cream that was fermented by lactobacilli at 37 °C for 24 h. Physicochemical analysis, proximate analysis and rheology properties of LH-butter were compared with butter produced using unfermented cream (control). LH-butter showed a significantly (P<0.05) higher fat content and acid value; lower moisture and ash; and was softer than the control. Cream fermentation modified nutritional and textural properties of butter in which LH-butter contained higher health beneficial unsaturated fatty acids than the control and thus rendered the product softer. Its enrichment with probiotics could thus further enhance its functional property.
In this study, the methods for extraction and purification of miraculin from Synsepalum dulcificum were investigated. For extraction, the effect of different extraction buffers (phosphate buffer saline, Tris-HCl and NaCl) on the extraction efficiency of total protein was evaluated. Immobilized metal ion affinity chromatography (IMAC) with nickel-NTA was used for the purification of the extracted protein, where the influence of binding buffer pH, crude extract pH and imidazole concentration in elution buffer upon the purification performance was explored. The total amount of protein extracted from miracle fruit was found to be 4 times higher using 0.5M NaCl as compared to Tris-HCl and phosphate buffer saline. On the other hand, the use of Tris-HCl as binding buffer gave higher purification performance than sodium phosphate and citrate-phosphate buffers in IMAC system. The optimum purification condition of miraculin using IMAC was achieved with crude extract at pH 7, Tris-HCl binding buffer at pH 7 and the use of 300 mM imidazole as elution buffer, which gave the overall yield of 80.3% and purity of 97.5%. IMAC with nickel-NTA was successfully used as a single step process for the purification of miraculin from crude extract of S. dulcificum.
Resistant starch has potential health benefits but the factors affecting its formation in bread and baked products are not well studied. Here, the formation of resistant starch in wholemeal bread products was evaluated in relation to the processing conditions including fermentation time, temperature and the inclusion of palm oil as a vitamin source. The effects of each the factor were assessed using a full factorial design. The impact on final starch content of traditional sourdough fermentation of wholemeal rye bread, as well as the bulk fermentation process of wheat and wheat/oat blends of wholemeal bread, was also assessed by enzyme assay. Palm oil content was found to have a significant effect on the formation of resistant starch in all of the breads while fermentation time and temperature had no significant impact. Sourdough fermentation of rye bread was found to have a greater impact on resistant starch formation than bulk fermentation of wheat and wheat blend breads, most likely due the increased organic acid content of the sourdough process.
The trace metal concentrations in edible muscle of red tilapia (Oreochromis spp.) sampled from a former tin mining pool, concrete tank and earthen pond in Jelebu were analysed with microwave assisted digestion-inductively coupled plasma-mass spectrometry. Results were compared with established legal limits and the daily ingestion exposures simulated using the Monte Carlo algorithm for potential health risks. Among the metals investigated, arsenic was found to be the key contaminant, which may have arisen from the use of formulated feeding pellets. Although the risks of toxicity associated with consumption of red tilapia from the sites investigated were found to be within the tolerable range, the preliminary probabilistic estimation of As cancer risk shows that the 95th percentile risk level surpassed the benchmark level of 10(-5). In general, the probabilistic health risks associated with ingestion of red tilapia can be ranked as follows: former tin mining pool > concrete tank > earthen pond.
An HS-SPME method was developed using multivariate experimental designs, which was conducted in two stages. The significance of each factor was estimated using the Plackett-Burman (P-B) design, for the identification of significant factors, followed by the optimization of the significant factors using central composite design (CCD). The multivariate experiment involved the use of Minitab® statistical software for the generation of a 2(7-4) P-B design and CCD matrices. The method performance evaluated with internal standard calibration method produced good analytical figures of merit with linearity ranging from 1 to 500 μg/kg with correlation coefficient greater than 0.99, LOD and LOQ were found between 0.35 and 8.33 μg/kg and 1.15 and 27.76 μg/kg respectively. The average recovery was between 73% and 118% with relative standard deviation (RSD=1.5-14%) for all the investigated pesticides. The multivariate method helps to reduce optimization time and improve analytical throughput.
Food falsification has direct impact on public health, religious faith, fair-trades and wildlife. For the first time, here we described a multiplex polymerase chain reaction assay for the accurate identification of five meat species forbidden in Islamic foods in a single assay platform. Five pairs of species-specific primers were designed targeting mitochondrial ND5, ATPase 6, and cytochrome b genes to amplify 172, 163, 141, 129 and 108 bp DNA fragments from cat, dog, pig, monkey and rat meats, respectively. All PCR products were identified in gel-images and electrochromatograms obtained from Experion Bioanalyzer. Species-specificity checking against 15 important meat and fish and 5 plant species detected no cross-species amplification. Screening of target species in model and commercial meatballs reflected its application to detect target species in process foods. The assay was tested to detect 0.01-0.02 ng DNA under raw states and 1% suspected meats in meatball formulation.
A new computational approach for the determination of 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (DPPH-RSA) in food is reported, based on the concept of machine learning. Trolox standard was mix with DPPH at different concentrations to produce different colors from purple to yellow. Artificial neural network (ANN) was trained on a typical set of images of the DPPH radical reacting with different levels of Trolox. This allowed the neural network to classify future images of any sample into the correct class of RSA level. The ANN was then able to determine the DPPH-RSA of cinnamon, clove, mung bean, red bean, red rice, brown rice, black rice and tea extract and the results were compared with data obtained using a spectrophotometer. The application of ANN correlated well to the spectrophotometric classical procedure and thus do not require the use of spectrophotometer, and it could be used to obtain semi-quantitative results of DPPH-RSA.
A solvent displacement method was used to prepare lutein nanodispersions. The effects of processing parameters (addition method, addition rate, stirring time and stirring speed) and emulsifiers with different stabilizing mechanisms (steric, electrostatic, electrosteric and combined electrostatic-steric) on the particle size and particle size distribution (PSD) of the nanodispersions were investigated. Among the processing parameters, only the addition method and stirring time had significant effects (p<0.05) on the particle size and PSD. For steric emulsifiers, Tween 20, 40, 60 and 80 were used to produce nanodispersions successfully with particle sizes below 100nm. Tween 80 (steric) was then chosen for further comparison against sodium dodecyl sulfate (SDS) (electrostatic), sodium caseinate (electrosteric) and SDS-Tween 80 (combined electrostatic-steric) emulsifiers. At the lowest emulsifier concentration of 0.1%, all the emulsifiers invariably produced stable nanodispersions with small particle sizes (72.88-142.85nm) and narrow PSDs (polydispersity index<0.40).