Natural preservatives having the great antioxidant and antimicrobial activity have been utilized in the food industry for many years. In the present study, the effect of of two brands of commercial Assam green tea infusion (represented by A and B) and 0.02% BHA/BHT on microbial growth, anti-lipid oxidation and color change were investigated in cooked beef. The green tea concentration has influenced to the results. It was found that A and B at the concentration of 250 mg/mL significantly reduced the population of Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and E. coli in the cooked beef to an undetectable level within 2 days of storage at 4oC. A and B also exhibited higher anti-lipid oxidation activity compared to 0.02% BHA/BHT, and control. Assam green tea infusions in cooked beef significantly increased ∆ L*
value and decreased ∆ a* and ∆ b* value (p ≤ 0.05). These indicate that Assam green tea infusion might be a potential candidate as a natural preservative for beef and other types of food.
Honey is usually subjected to filtration and heating for bottling before commercialization. However, there is no standard procedure available for thermal treatment on honey. Honey is thermally heated at various temperature and duration based on individual experience to prolong the shelf life of honey in the market. The heating methods might decrease the biochemical components such as nutrients, enzymatic activities and vitamins to certain extent. In addition to water reduction, thermal treatment on sugar rich honey usually accompanied by the formation of 5-hydroxymethylfurfural (HMF). In the present study, the biochemical components in three commonly consumed honey in Malaysia, namely tualang, gelam and acacia honey were investigated before and after thermal treatment at 90oC for 30 min. The short period of heating time was found to degrade nutrients, enzymatic activities and water soluble vitamins in honey. The degradation of protein and enzyme via proteolytic digestion had attributed to the increase of free amino acids in honey. Based on the multivariate analysis, the most thermally affected biochemical components are crude fat, panthotenic acid (Vitamin B5) and diastase activity which explain for 86.4% of the total variance. The kinetic studies on the HMF formation revealed that the honey samples followed zero order kinetic model for the first 60 min of heating at 90oC. The findings indicate that the temperature and duration of heating during honey processing is essential to be investigated according to the honey origin. The initial biochemical composition of honey would affect the kinetic profile of HMF formation.
Water and ethanolic extracts of four Malaysian local herbs, Tenggek burung (Melicope Iunu-ankenda), Kesum (Polygonum minus), Curry leave (Murraya Koenigii) and Salam (Eugenia polyantha) were investigated for their total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activities (AA). Total phenolic content (TPC) of the herbs was determined using Folin-Ciocalteu reagent assay while the total flavonoid content (TFC) was determined based on aluminium chloride-flavonoid assay. The determination of AA was done using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activitiy and β-carotene bleaching assays (BCB). Different extraction solvents significantly affected the TPC, TFC and AA of all herbs studied (p < 0.05). Both Tenggek burung and Kesum showed highest TPC, TFC and AA regardless of extraction solvents compared to Curry leave and Salam. All herbs showed strong positive correlation between TPC and DPPH assay. However, negative and low correlation between TFC and AA were obtained for all herbs studied. This showed that phenolic compounds of certain structures were responsible for the AA of all the herbs in this study. In conclusion, all herbs in this study except curry leave could be inexpensive sources of good natural antioxidants with nutraceutical potential in food industry.
This study aimed to optimise potential extraction conditions using response surface methodology (RSM) for yielding maximum levels of total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging capacity of henna (Lawsonia inermis) stems. The ranges for selected independent variables, namely acetone concentration (20−90%, v/v), extraction time (10−90 min), and extraction temperature (25−45°C) were identified by screening tests. Optimum conditions obtained for extraction of TPC were 47.0% acetone, extraction time of 47.6 min and extraction temperature of 37.3oC. The result also showed that 75.8% acetone, extraction time of 26.2 min and extraction temperature of 41oC yielded the highest DPPH• scavenging capacity. The optimized extraction conditions have resulted in TPC and DPPH• scavenging capacity of 5232.4 mg GAE/100 g DW and 6085.7 mg TE/100 g DW, respectively which similar to the predicted values. Therefore, RSM has successfully optimized the extraction conditions for TPC and radical scavenging capacity of henna stems.
The inhibitory effect of onion extract on cassava leaf polyphenol oxidase was investigated. The polyphenol oxidase from cassava leaves was strongly inhibited by various anti-browning agents such as L-ascorbic acid and L-cysteine. The percentage of inhibition increased with the increased of anti-browning agents concentrations. The addition of heated onion extract exhibited a stronger inhibitory effect on cassava leaf polyphenol oxidase than the fresh onion extract. The highest percentage of inhibition was exhibited with heated onion extract in the presence of glucose and glycine, which was 87.18%. The onion extract inhibited the cassava leaf polyphenol oxidase non-competitively.
Proximate composition, pH and amylose content of ripe Cavendish banana flour (RBF) prepared in this study were compared with all-purpose wheat flour (WF). RBF was found to be significantly (P < 0.05) higher in total carbohydrates and minerals content, while significantly (P < 0.05) lower in protein and fat contents compared with those of WF. Wheat-ripe banana composite flours (W-RBF) prepared by partial substitution of WF with RBF were assessed for swelling power, solubility, pasting properties and gel textural properties. Granular swelling of RBF occurred at a higher temperature compared to that of WF, suggesting that more energy and water were required to cook WF-RBF as the presence of soluble carbohydrates would compete for water and this would eventually delay starch hydration and granular expansion during cooking. Higher substitution with RBF led to higher soluble carbohydrates content, and increase in solubility index of WF-RBF. Partial substitution with RBF also resulted in significant (P < 0.05) decrease in pasting properties. A higher substitution of WF with RBF could reduce starch gelatinisation during cooking and retrogradation owing to the reduction of available starch in WF-RBF. All WF-RBF gels were significantly (P < 0.05) firmer and less sticky compared to WF gels.
MeSH terms: Amylose; Cooking; Dietary Carbohydrates; Flour; Gelatin; Gels; Hot Temperature; Minerals; Solubility; Starch; Temperature; Water; Triticum; Musa
In the current research, osmotic dehydration of red pitaya (Hylocereus polyrhizusis) cubes using sucrose solution at mild temperature (35ºC) was investigated. Sucrose solution (40, 50 and 60% w/w) was employed for osmotic dehydration process. Responses of weight reduction (WR), solid gain (SG), water loss (WL), color (L*, a* and b*) and texture (hardness) were evaluated. It was found that sucrose concentration significantly (p < 0.05) affected the mass transfer terms during osmosis process. The results obtained revealed an increase in yellowness (b*), decrease in lightness (L*) and redness (a*) as the sucrose concentration increased. Furthermore, osmotically dehydrated samples were considerably softer than untreated samples. Increasing of sucrose concentration and dehydration time caused softer tissue of dehydrated product compared with the fresh red pitaya.
The effect of chamber pressure of a freeze dryer on essential oil contents, drying kinetics, drying characteristics lemon balm leaves and morphology of lemon balm glandular trichomes (oil reservoirs) were investigated. It was found that overall freeze drying (FD) carried out at high (FD-HP) and low pressure (FD-LP) settings consist of sublimation rate, first falling rate and second falling rate periods. Drying rate of FD-LP dried Lemon Balm leaves are higher than FD-HP dried samples, where the drying rates ranged from 0.063 to 0.449 g H2O/ g DM. s and 0.0365 to 0.395 g H2O/ g DM. s, respectively. 3rd order Polynomial model was found to be the best fit model for both drying kinetics. In terms of product quality, eight (8) major constituents of lemon balm leaves essential oil were quantified. Further to this, electro-microscope was used to observe the peltate glandular hairs structure. Product quality analysis showed that FD-HP retained higher amount of essential oil, shape of glandular hairs, but no positive effect on the freeze drying duration.
MeSH terms: Accidental Falls; Desiccation; Freeze Drying; Hair; Kinetics; Oils, Volatile; Pressure; Sublimation; Models, Statistical; Oil and Gas Fields; Trichomes
The demand for novel antimicrobial agents from natural resources has been increased worldwide for food conservation purpose. In this study antimicrobial activity of musk lime, key lime and lemon were evaluated against various food borne pathogens and spoilage bacteria using disc diffusion test. Type of extraction solvent and concentration level significantly influenced the antibacterial activity of all the extracts. Ethanol extracts of musk lime, key lime and lemon exhibited significant broadest inhibitory activity at 100% concentration level (pure extract) compared to water and juice extracts. 100% ethanol extracts of musk lime (39.7 mm), key lime (26.7 mm) and lemon (32.0 mm) exhibited the largest diameter of inhibition zone (DIZ) against Aeromonas veronii. 100% water extracts of musk lime (25.3 mm), key lime juice extract (23.3 mm) and water extracts of lemon (23.7 mm) was most effective against food spoilage bacteria, A. veronii. The prominent results of the antimicrobial activity from lime, key lime and lemon extracts may attribute them as potential natural food preservatives and could be used in pharmaceuticals field.
Kenaf (Hibiscus cannabinus) seeds have always being wasted as agricultural waste. Recent studies revealed that the seeds contain high fiber. The purpose of this study is to develop defatted kenaf seeds yellow noodles (DKSY) and assess the nutritional and physicohemical properties of the noodles. Defatted kenaf flour at 25% and 75% were used to make DKSY noodles and compared to wheat yellow noodles (Control). Fresh DKSY noodles were analyzed for their nutritional and physiochemical properties. The ash and fiber contents increased in order of Control > 25% DKSY > 75% DKSY noodles. While total phenolic contents (TPC) was found to be higher in 75% DKSY noodles (138.30 ± 1.63 mg GAE/100 g) than Control noodles. Colour (L, b) and hardness decreased in order of Control > 25% DKSY > 75% DKSY indicating that DKSY noodles developed less quality than Control noodles. However, cooking loss values were found to be in the same order while cooking values exist in the opposite order indicating that. DKSY noodles have better noodle cooking quality. In conclusion, nutritional properties and noodle cooking quality of yellow noodles increased with higher concentration of defatted kenaf flour but the physicochemical properties were compromised. More research needs to be done in order to develop a formulation that can increase all of the attributes studied.
Channa striatus (“haruan”) fish destined for fillet preparation was subjected to two freezing treatments, freezing with distilled water (FW) or freezing directly without distilled water (DF). Fish that was freshly processed without freezing served as control (C). Fillet yield (%) was in the range 33.8% to 35.3% and the highest yield was recorded in FW samples. Whole Fillet Powder (WFP) was prepared from the fillets through low temperature vacuum oven drying (50°C) and its composition and physicochemical properties were assessed. There was no significant difference in moisture and protein contents of all samples (p > 0.05). All WFP were generally dark in colour with whiteness indices ranging from 55.23 - 63.98. The redness (a*) values were 4.33, 11.12, 8.83 whilst the yellowness (b*) were 19.31, 23.04, 21.20 for C, WFP-FW and WFP-DF respectively. WFPs were generally high in histidine, arginine, threonine and tyrosine when compared to egg whites and these (except histidine) and other amino acids (serine, glycine, methionine and phenylalanine) were significantly higher (p < 0.05) in WFP-FW compared to other samples. Overall, freezing treatments affected the composition and physicochemical properties of WFPs.
The aims of this study were to examine the effect of salts (CaCl2, CaSO4 and MgSO4) on the rheological and thermal properties of gelatin extracted from the skins of tropical fishes, sin croaker (Johnius dussumeiri) and shortfin scad (Decapterus macrosoma). It was found that the melting temperatures of fish skin gelatins were increased by 1.5 times as compared to bovine gelatin which was only increased by 0.5 times after holding for 2 h at 5°C. The storage (G’) and loss (G”) modulus of fish skin gelatins were improved with the addition of calcium sulphate (CaSO4) and magnesium sulphate (MgSO4), respectively. However, the storage (G’) and loss (G”) modulus of gelatin solutions were decreased with the addition of calcium chloride (CaCl2). Magnesium sulphate (MgSO4) was found to be an effective salt to improve the bloom value, elastic and viscous moduli of the fish skin gelatin. This study showed that shortfin scad skin gelatin with salt addition possessed better thermal and rheological properties than sin croaker gelatin.
Some vegetable oils contain natural antioxidants such as beta carotene and vitamin E namely alpha tocopherol. The objective of this study was to screening the value of α-tocopherol, β-carotene, antioxidant capacity, antimicrobial activity and toxicological properties of roasted pili nut oil (RPNO) and unroasted pili nut oil (UPNO). The result showed that RPNO contained higher amount of vitamin E and less amount of beta carotene compared to UPNO. RPNO and UPNO scavenged DPPH radicals by 24.66% and 9.52% at concentration of 140 μg/ml. The total phenolic compound (TPC) in UPNO and RPNO were about 19.96 ± 0.52 mg/kg and 12.43 ± 0.69 mg/kg respectively. It was observed that bacteria species exhibited different sensitivities towards RPNO, UPNO, Gentamycin, Ampicillin and Chloramphenicol. Bacillus cereus 14570 was the most sensitive bacterium and all strains of Staphylococcus aureus tested were resistant against both samples RPNO and UPNO. An in vitro toxicological study based on the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) cytotoxicity assay was also performed. In vitro cytotoxicity indicated that both RPNO and UPNO had no effect against HeLa (cervical cancer cell), MCF-7 (breast cancer cell) and HT-29 (human colon adenocarcinoma cell) cell lines tested.
Canarium ovatum oil Engl. (pili nut oil) was extracted by using cold press method and then the
physico-chemical properties of the oil samples, roasted pili nut oil (RPNO) and unroasted pili
nut oil (UPNO) such as iodine value (IV), peroxide value (PV), acid value (% FFA), solid fat
content (SFC), fatty acid composition and triacylglycerol (TAG) composition were determined.
The percentage of oil yield and iodine value for RPNO and UPNO were showed no significant
different, wheareas there were significantly different for the peroxide value and percentage of
free fatty acid. The solid fat content for RPNO and UPNO were similar to the palm olein oil
and both completely melt at 25°C. Both samples, RPNO and UPNO were contained 50.70%
and 52.59% of oleic acid and were found not contain the trisaturated TAGs.
A study was carried out to compare the composition and thermal profiles of the fat component of six brands of commercial biscuits (BA, BB, BC, BD, BE & BF) with those of lard and palm oil. Extraction of fat from biscuit samples was done using petroleum ether according to the soxhlet extraction procedure. The isolated fat samples along with lard and palm oil were analyzed using gas liquid chromatography (GLC), reversed-phase high performance liquid chromatography (RP-HPLC), and differential scanning calorimetry (DSC). According to GLC analysis, palm oil, lard and all six biscuit brands had either palmitic or oleic acid as major fatty acids. Sn-2 positional analysis of fatty acids showed that oleic (> 60%) as the most dominant fatty acid of palm oil and biscuit brands BA, BB, BC, and BD while palmitic (> 60%) as the most dominant fatty acid of lard and biscuit brands BE and BF. RP-HPLC analysis showed that the triacylglycerol (TAG) profiles of lard and biscuit brands BE and BF were closely similar while those of brands BA, BB, BC, and BD and palm oil were similar. DSC analysis showed that the cooling and heating profiles of lard and brands BE and BF were similar, while those of palm oil and brands BA, BB, BC, and BD were similar. Hence, this study concluded that biscuit brands BE and BF are not suitable for consumers whose religious restriction prohibit the use of lard as food ingredient.
The effect of ribose-induced Maillard reaction on the physical and mechanical properties of gelatin films was investigated. Bovine gelatin solution (5 g/100 mL) containing glycerol and sorbitol (1:1) was mixed with 20% (R20), 40% ribose (R40), or 40% sucrose (S40) (weight % is based on gelatin dry weight) followed by heating (90ºC, 2 h) and oven drying to produce dried gelatin films. R20 and R40 films were brownish in color with lower light transparency, while CF (control film; without sugars) and S40 were colorless and had higher transparency. Tensile strength and Young Modulus values of the films were in the order; CF > R20 > R40 > S40, while elongation at break was in the order; R40 > S40 > R20 > CF. Water solubility and swelling percentages of the films were in the order; CF > S40 > R20 > R40, indicating the occurrence of insoluble “Maillard complexes” within R20 and R40 films. R20 and R40 films showed maximum light absorption at wavelength of 200 − 350 nm, whilst S40 and CF showed maximum absorbance at 200 − 250 nm. The addition of ribose yielded gelatin films with increased protection against UV light, even though the presence of sugars might had disrupted the inter connection of junction zones and decrease in mechanical properties. Occurrence of the Maillard reaction within R20 and R40 films could be the main reason for differences in physical and mechanical properties of films containing ribose that were formed from heated film-forming solutions.
The effects of soaking conditions on the quality characteristics of seaweed paste of Kappaphycus alverazii species were studied. Response Surface Methodology (RSM) with a 2-factor, 5-level central composite design (CCD) was conducted to determine the optimum soaking conditions. The interactive effect of dry seaweed: soaking water ratio (X1 = 1: 15-50) and soaking duration (X2 = 30-120 min) on the gel strength (g), whiteness, expansion (%), moisture content (%) and protein content (g/100 g) of the paste were determined. Results showed that the experimental data could be adequately fitted into a second-order polynomial model with multiple regression coefficients (R2) of 0.8141, 0.9245, 0.9118, 0.9113 and 0.9271 for the gel strength, whiteness, expansion, moisture content and protein content, respectively. The gel strength, whiteness, expansion, moisture content and protein content of seaweed paste were dependent on the ratio of dry seaweed to soaking water and also soaking duration. The proposed optimum soaking conditions for the production of seaweed paste is at a ratio of 1:15 (dry seaweed : soaking water) and soaking duration of 117.06 min. Based on the result obtained, the RSM demonstrated a suitable approach for the processing optimization of Kappaphycus alverazii paste.
The use of herbal preparations remained the main approach of folk medicine to the treatment of ailments and debilitating diseases. Initial intensive researches conducted on Lemongrass extracts (tea) may have showed conflicting evidences, however the resurgence in claims of folk medicine practitioners necessitated further inquiry into the efficacy of the tea. Lemongrass tea contains several biocompounds in its decoction, infusion and essential oil extracts. Anti-oxidant, anti-inflammatory, anti-bacterial, anti-obesity, antinociceptive, anxiolytic and antihypertensive evidences of lemongrass tea were clearly elucidated to support initial pharmacological claims. Lemongrass tea was non-toxic, non-mutagenic and receives wide acceptance among alternative medicine practitioners in several developing countries. This review therefore presents previous research activities, technologies and information surrounding bioactivities of lemongrass tea. Areas of future researches which may elucidate mechanisms of the biological properties of lemongrass extracts were highlighted.
This study is carried out to determine the physical properties of green pepper berries and to
improve the existing retting technique in white pepper production using the Viscozyme and
Celluclast as the enzymes. Effects of blanched and non-blanched pepper berries, acidic solution
and non-acidic solution, and different temperature of 28, 35, 42, and 49°C are determined to
obtain the optimum conditions for enzymatic retting. The physical properties of green pepper
berries such as dimension (5.21 mm), weight (0.11 g per berry), true density (1319.33 kg/m3),
bulk density (596.9 kg/m3), sphericity (0.976), angle of repose (6.87°) and flow ability with
funnel flow time of 5.27 seconds were determined. The enzymatic retting in 42oC can fully
soften the pericarp of pepper berries from 15 days to 7 days. The enzymatic decortication has
the efficiency in acidic solution (pH 4) and temperature of 42°C with non-blanched pepper
berries. The enzymatic retting reached constant fracture force (20.98N) at the ninth soaking
days while the non-enzymatic retting reached constant fracture force (21.89N) at the fifteenth
soaking days.
The study examined the protein profile of Pectoralis major muscle in broiler chickens subjected to different freezing and thawing methods. Pectoralis major muscle was excised from the carcasses of twenty broiler chickens and split into left and right halves. The left half was subjected to slow freezing (-20oC) while the right half was rapidly frozen (-80oC). The samples were stored at their respective temperature for 2 weeks and assigned to either of tap water (27oC, 30 min), room temperature (26oC, 60 min), microwave (750W, 10 min) or chiller (4oC, 6 h) thawing. Changes in myofibrillar proteins following the thawing methods were monitored through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The electrophoretic profile indicated differences (p < 0.05) in intensities of the components of myofibrillar proteins among the thawing methods in both slow and rapidly frozen samples. Chiller thawing had significantly higher (p < 0.05) protein concentration than other methods in rapidly frozen samples. However, in slow freezing, there were no significant differences in protein concentration among the thawing methods. In rapidly frozen samples, the protein optical densities at molecular weight of 21, 27, 55 and 151kDa in tap water, chiller and room temperature thawing did not differ (p < 0.05). Similarly, in slowly frozen samples, protein optical densities at molecular weight of 21, 27, 85 and 151 kDa were not significantly different among chill, tap water and room temperature thawing. Microwave thawing consistently caused higher protein degradation resulting in significantly lower (p < 0.05) protein quality and quantity in both freezing methods.