Staphylococcus aureus is the leading cause for foodborne diseases. Extensive use of antibiotics has led to emergence of antibiotic-resistant S. aureus. Hence, interest on natural plant-based alternative which limits the use of synthetic chemicals is growing. The present work evaluated the antibacterial capacity of garlic, aloe vera, galangal, pineapple peel, neem, papaya leaf, lemongrass, peppermint, nutmeg and clove separately extracted with hexane, ethanol and water to a final concentration of 10% w/v against ampicillin+penicillin-resistant isolates of S. aureus in vitro. Streptomycin was used as a drug control against the resistant isolates; BRS023, BRS068 and DRS072. According to the interpretive standards for inhibition zone diameter provided by the Clinical and Laboratory Standards Institute, isolates BRS068 and DRS072 were considered resistant (≤ 12 mm), and isolate BRS023 was considered intermediate (13-14 mm). Against these isolates, all crude plant extracts exhibited varying degrees of inhibition. However, a coherent trend was observed in the inhibition between resistant and intermediate isolates regardless of plants and solvents used. It was also found that extraction solvent types impacted the resulting antibacterial activity. In terms of positive inhibition, the solvents were ranked in the order of hexane (77%) > water (73%) > ethanol (57%). 10% hexane extract of galangal gave the overall highest inhibition zones (17.8 ± 1.4 mm) closely followed by 10% ethanol extract of nutmeg (16.3 ± 1.1 mm). Further phytochemical analyses of the antibacterial compounds from galangal and nutmeg, and their minimum inhibitory concentration (MIC) are needed. Potential applications of plant-based antibacterial compounds as natural, costeffective and less-toxic food preservatives against drug-resistant foodborne pathogens should be explored.
Microwave heating technology is widely used in food catering and domestic households. Nonuniformity of microwave temperature distribution causes the formation of hot and cold spots in heated product has led to the survival of foodborne pathogens which may later cause food borne diseases. It is the aim of this study to determine the effect of different microwave heating on the microbiological quality of microwavable frozen chicken curries. Nine commercialised frozen chicken curries were thawed overnight in the chiller (< 4°C) and exposed to different microwave power levels and times (270 W at 60 s; 950 W at 150 s and 300 s). 25 g of chicken curry were homogenised, serial diluted and enumerated aseptically. Total Aerobic Count (TAC), Total Coliform Count (TCC), Escherichia coli count and Salmonella count were carried out and no microorganisms were detected. Enterobacteriaceae were found in the food samples after enrichment process. Polymerase Chain Reaction (PCR) amplification and 16S ribosomal ribonucleic acid (rRNA) sequencing were carried out. Results of 16S rRNA sequence analysis indicated that two gram-negative isolates after enrichment were identified as Klebsiella pneumoniae.
Paddy is the staple food of local people in Sabah, but its production is affected by a disturbing disease known as blast, which is caused by fungi (i.e., Magnaporthe grisea and Magnaporthe oryzae) infection. Knowledge regarding distribution of blast-resistant (BR) genes among various Sabah traditional paddy varieties in different divisions of Sabah is not clear; hence, molecular identification of BR genes in Sabah traditional paddies is urgently needed. In this study, genomic DNA was extracted from 21 different Sabah traditional paddy varieties collected from three divisions of Sabah including the West Coast Division (WCD), Sandakan Division (SD), and Interior Division (ID). The presence of 11 BR and 2 pathogenesis-related (PR) genes in their genome was molecularly screened using a PCR approach and validated using direct sequencing. Our results showed that high frequencies of Pib (95.2%), pi-ta (100.0%), and RCC2 (100.0%) genes were obtained in all 21 Sabah traditional paddy varieties screened. Interestingly, one of the paddy varieties from ID of Sabah, PBT23, did not contain the Pib gene but carried the Pita/Pita-2 allele in its genome. Besides, only three paddies (PBT08 and PBT07 from WCD, and PBT23) exhibited the Pik-p gene, and no varieties were found to carry the Pik, Pik-m, Pit, Piz, Piz-t, Pi-ta, Pi9, and wwin2 genes. In conclusion, this study serves as the basis for improvement and effectual management of traditional paddies in different divisions of Sabah towards blast resistance with knowledge of BR or PR genes inherited in their genome.
Soymilk, which can be called as plant based “milk” is a favourite traditional beverage in Asian with various beneficial health protective effects due to the presence of isoflavones. Mixing cereal grains into soymilk to make a wholesome beverage for breakfast becomes popular. However, dietary factors may affect the bioaccessibility of isoflavones. The aim of this current work was to evaluate changes in the bioaccessibility of isoflavones in soymilk after mixing with selected cereal grains following in vitro gastrointestinal digestion. The samples were subjected to in vitro gastrointestinal digestion with its isoflavones content determined before and after simulated gastric digestion and intestinal digestion with dialysis membrane. Soymilk contained 1.80 ± 0.03 mg daidzein and 2.12 ± 0.08 mg genistein in 100 ml, while bioaccessibility of soymilk daidzein and genistein were 11.24 ± 0.46% and 5.09 ± 0.25% respectively. The addition of cereal grains except barley in soymilk showed significant reduction (p
High lipid levels are associated with the increase tendency of atherosclerosis formation. In the pathogenesis of atherosclerosis, increase in low density lipoprotein cholesterol (LDL-c) concentration has been identified as the main culprit in many cardiovascular disease (CVD) incidents. Both quercetin and kaempferol are flavonoids that most abundantly found in fruits and vegetables. Several studies have dictated that both compounds exhibit CVD protective effects through the regulation of lipid levels. In the present study, the hypolipidemic potential of quercetin and kaempferol through LDL-c uptake were tested on HepG2 cells. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in order to study the cytotoxicity effect quercetin and kaemperol on cell proliferation. The present study demonstrated that quercetin and kaempferol at low concentration of 15 µM, possess the highest hypolipidemic effects via LDL-c uptake in HepG2 cells (p
Gelatin from goatskin pretreated with hydrochloric acid and extracted with distilled water at 60oC for 9 hours was characterized and compared to that of bovine skin gelatin (BSG). A yield of 10.26% (wet weight basis) was obtained. Goatskin gelatin (GSG) had high protein (86.58%), suitable moisture (9.58%), low fat (1.46%) and low ash (0.11%) content. The functional properties of GSG including gel strength (301 g bloom) and emulsion activity index (94.27%) were higher than the functional properties of BSG including gel strength (192 g bloom) and emulsion activity index (49.74%). The foaming property of GSG (102%) was lower than that of BSG (164.67%). This study shows that GSG has a high potential for application as a source of commercial gelatin.
Cruciferous vegetables belong to the mustard family of plants such as Brussels sprouts, kale, broccoli, cabbage and cauliflower. They are well known for their cancer prevention properties which are due to high content of bioactive compounds, isothiocyanates (ITCs). This study was aimed to investigate nitrosation inhibition ability of the cruciferous vegetables commonly consumed with meat products namely, broccoli, cauliflower and cabbage. Aqueous extracts of fresh and steamed (2 and 4 min) vegetables were subjected to determination of antioxidant capacity (DPPH and FRAP assay) and chemical composition i.e. total phenolic and isothiocyanate (ITC) content. It was found that TPC, DPPH and FRAP values of raw vegetables were different in each vegetable and ranged from 17.12-38.91 mg GAE/100 ml, 44.09-63.31% and 1.36-6.81 mg TE/100 ml, respectively. Among three types of cruciferous vegetable, broccoli had the highest PEITC content being 0.21 mmol/100 g compared to cauliflower (0.15 mmol/100 g) and cabbage (0.06 mmol/100 g). Moreover, it was found that steaming process significantly enhanced antioxidant activity, TPC as well as PEITC content in a timedependent manner up to 4 min (p
Supercritical carbon dioxide (scCO2) extracted mango seed fat (MSF) was blended with palm oil mid-fraction (POMF) to obtain cocoa butter replacers (CBRs). The fatty acid constituents and physicochemical properties of the formulated blends were analysed by gas chromatography (GC). In this study, the fatty acid constituents and other physicochemical properties such as iodine value (43.2 to 43.4 g I2/100 g fat), saponification value (195.7 to 195.9 mg KOH/g fat), acid value (2.1 to 2.7%), and slip melting point (33.8 to 34.9°C) of blends MSF/POMF at ratios 85/15, 80/20, 75/25, and 70/30 were found similar to the physicochemical properties of commercial cocoa butter. Thus, it could be concluded that the MSF/POMF blends that are blends 85/15, 80/20, 75/25, and 70/30 (3 to 6) could be suggested as CBRs in terms of the physicochemical properties like fatty acid constituents, iodine, saponification and acid values and slip melting point.
β-carotene, a type of provitamin A, is beneficial to our health. However, the compound needs to be released from its food matrix before being utilised by the body. Thus, understanding the bioaccessibility of β-carotene in the food consumed is a crucial step. The objective of this study was to determine the effect of various cooking methods on bioaccessibility of β-carotene in pumpkin and butternut squash. In vitro digestion was carried out on raw and cooked (steamed, boiled, and deep-fried) pumpkin and butternut squash. β-carotene was identified using RPHPLC. Generally, butternut squash (4.99±0.02mg/100g) had higher β-carotene content than pumpkin (4.34±0.04mg/100g). Thermal processing resulted in lower β-carotene content in pumpkin samples; however, it increased the β-carotene content in butternut squash samples. In term of bioaccessibility, thermal processes increased the percentage of bioaccessible β-carotene in both pumpkin and butternut squash samples. Raw pumpkin had 10.56±0.44% of bioaccessible β-carotene while raw butternut squash had only 1.65±0.04%. Bioaccessibility of β-carotene in deep-fried pumpkin and butternut squash were significantly higher than their raw sample with 68.86±0.86% (p
Tropical fruits are of great significance in human diet due to abundant nutritional and antioxidants components. The processing or consumption of these fruits generates waste,which is generally disposed of into the ecosystem. However, efforts are in line to evaluate the nutritional worth and possible reuse of fruit processing waste by valorizing the waste in an optimal way. In this review, by-products of rambutan fruit waste, i.e., seed and peel, are signified with respect to their nutritional values and possible applications. Peel and seed cumulatively share almost around 50% of whole rambutan fruit by weight. Peel that is rich in phenolics and ellagitannins have applications as a natural antioxidant system. However, abundant fat content (14−41%) with high oleic acid, renders the seed a novel source of vegetable fat. Besides, possibilities of using seed fat in chocolate (30 wt.% substitute) and personal care products are also one of the focus. Nanostructured seed fat is reported for encapsulation off at-soluble vitamins (e.g., vitamin E). Additionally, the seed contains the most of the essential and non-essential amino acids that are concentrated as protein concentrate. The physico-functional properties of defatted seed flour and seed mucilage are also elaborated. Similarly, rambutan seed oil and peel utility as filler in packaging, bio-coagulant, bio-sorbent and alternative biodiesel are also mentioned. Despite diverse applications, gaps are still there to further evaluate and validate the potential of rambutan processing by-products. Thus, to avail the manifold potential, fruit by-products’ applications should be scaled up to transform the maximum waste into best.
This study was conducted to evaluate umami taste in protein hydrolysate produced from green mussel (Perna viridis) by hydrolysing with flavorzyme at pH 8, enzyme substrate ratio (E/S) 3% with or without the presence of 0.4% sodium tripolyphosphate (STPP) and 1.5% NaCI. Degree of hydrolysis (DH), yield, amino acid compositions, molecular weight distribution and sensory evaluation were determined. The highest DH (23.18%), darkest color and highest yield (8.34%) were recorded for hydrolysate produced in the presence of both STPP and NaCI. Electrophoresis analysis showed the presence of protein bands between 10 to 70 kDa where hydrolysate with addition of STPP and NaCI had bands with lower intensities. Amino acids which contribute to the umami taste such as glutamic acid, glycine and aspartic acid were higher in hydrolysate produced with STPP and NaCI addition. The hydrolysate has lesser fishy odor and flavor than those produced with only in the presence of flavorzyme and was also rated with highest score for all the five basic tastes including bitterness. However, the score for bitterness was still lower than the reference solutions. Therefore, green mussel hydrolysate produced in this study has a good potential as a food flavorant.
The glycemic index (GI) was conducted on 14 healthy subjects who have consumed 25 g of available carbohydrate portions of glucose (standard food) and four test foods (red-fleshed seedless watermelon, red-fleshed seeded watermelon and yellow-fleshed watermelon, as well as a glass of red-fleshed seedless watermelon juice) in random order after an overnight fast. Red-fleshed seedless watermelon was usually processed as juice than red-fleshed seeded and yellow-fleshed watermelon. Blood glucose was measured at 0, 15, 30, 45, 60, 90 and 120 mins after intake of the foods. Incremental areas under the curve were calculated, whereas the glycemic index was determined by expressing the area under the curve after the test foods, as a percentage of the mean area under the curve after consuming standard food, was carried out. The results showed that the area under the curve for a portion of red-fleshed seedless was 98.17±6.39, red-fleshed seeded (94.10±7.45), yellow-fleshed (92.95±8.73), and a juice of redfleshed seedless (98.89±6.38) did not have any significant difference (p
The aim of the present study is to report on the physicochemical characterization of shortfin scad (Decapterus macrosoma) waste hydrolysate (SWH) enzymatically prepared using alcalase. The characterization incorporates chemical composition (moisture, protein, fat, ash), protein concentration, molecular weight (SDS- PAGE), amino acid composition, solubility and structure properties of shortfin scad waste hydrolysate (SWH) via Fourier transform infrared (FTIR) spectroscopy. SWH contains an average of 5.06 ± 0.47% moisture, 73.08 ± 1.54% protein, 7.55 ± 0.90% fat and 10.40 ± 0.13% ash, with a high protein concentration (30.80mg/ ml). The SDS-PAGE result showed that molecular weight of SWH was less than 17kDa. The amino acid composition of SWH was found to be high in glutamic acid/glutamine (12.39 ± 0.59%) and aspartic acid/asparagine (7.89 ± 0.18%), followed by glycine (7.15 ± 0.39%), lysine (6.80 ± 0.15%), arginine (6.38 ± 0.08%), and leucine (5.99 ± 0.10%). Fourier transform infrared (FTIR) spectra showed that SWH presented a similar structure to that shortfin scad waste (SW). In addition, protein solubility in SWH increased to 92.98% by increasing pH level (pH 4 to pH 10). These findings demonstrate the promising potential of shortfin scad waste hydrolysate for the application as natural bioactive sources due to high protein content and concentration, lower molecular weight, high solubility, and high percentage of essential amino acids which fulfil adult human requirements.
The aims of this study are to isolate and characterize acid soluble collagen (ASC) and pepsin soluble collagen (PSC) extracted from silver catfish (Pangasius sp.) skin. Isolated ASC and PSC collagen were characterized in terms of chemical composition (moisture, protein, fat and ash content), protein concentration, functional group, solubility, and morphological properties as compared to commercial collagen. Yields of ASC and PSC were 4.27% and 2.27%, respectively. The chemical compositions of raw skin were 34.64%, 2.81%, 3.68%, and 0.31%, while the chemical compositions of ASC and PSC were 94.21%, 3.48%, 0.81%, 59.15%, and 88.25%, 3.46%, 0.92%, and 29.24%, for moisture, protein, fat, and ash, respectively. ASC and PSC had protein concentrations of 2.27 mg/mL and 2.70 mg/mL, respectively. Functional group analysis revealed that both isolated collagens exhibited Amide A, II and III as a fingerprint for collagen structure. The highest solubility was found at pH 4 for ASC, pH 1 for PSC, and pH 5 for commercial collagen. The morphology of the isolated collagens was porous and they contained fibril. In conclusion, the characteristics of the isolated ASC and PSC from silver catfish (Pangasius sp.) skin indicate that value-added collagen can be produced from the alternative source of freshwater fish.
The drying performance of industrial inclined bed dryer (IBD) and the milling quality of dried paddy was evaluated and compared in two main granary areas of Muda Agricultural Development Authority (MADA) and Integrated Agricultural Development Areas (IADA KETARA). A mix of MARDI’s paddy variety (MR 220 CL2 and MR 219) was used and the study on both granary area of MADA and IADA KETARA were carried out in local paddy mills located at Yan, Kedah and Besut, Terengganu respectively. The results indicated that the average drying rate in MADA was 119.93 kg water removed/hr whereas only 73.67 kg water removed/hr was recorded in IADA KETARA. Therefore, normalized water removal value of paddy mill in MADA was found higher than paddy mill in IADA KETARA. In terms of milling quality, average percentage of head rice yield of paddy mill in MADA and IADA KETARA was 76.89% and 73.87% respectively. The milling quality analysis of rice resulted from ANOVA found that there was no significant difference in the HRY and total broken between IBDs in both locations.
Viscosity and physical properties of flours and pastas prepared from four cultivars of green bananas (namely Pisang Berangan, Pisang Nangka, Pisang Tanduk, and Pisang Nipah) have been evaluated. The moisture content and water activity of banana flours were found in the range of 7.71%-8.50% wet basis and 0.33-0.37, respectively. The peak viscosity of banana flours were observed in the order of Pisang Tanduk > Pisang Nipah > Pisang Nangka > Pisang Berangan. The water activity and colour of pastas prepared from banana flours were lower and darker compared to wheat pasta. The firmness of banana flour dried pastas were observed significantly higher than wheat pasta, with Pisang Berangan pasta recorded the highest value of 446.53 ± 7.44 g. Among the green banana cultivars, pastas prepared from Pisang Nipah and Pisang Nangka flours are recommended for consumer who is preferred of bright colour and firm texture cooked pastas.
Yellowstripe scad fish (YSF) or Selaroides leptolepis belongs to the small pelagic group that is abundantly found in South China Sea and is categorised as low value fishes. This study is designed to explore the physicochemical properties of YSF protein hydrolysate extracted using sodium phosphate buffer followed by 0.5%-2.0% of Alcalase at a series of hydrolysis time (1 hr and 2 hr). The properties of freeze and spray dried protein hydrolysate were evaluated for yield, degree of hydrolysis, protein content, microstructure and water holding capacity. Results showed that prolonged hydrolysis time exhibited increasing yield (0.6%-1.6% for spray drying and 12-16% for freeze drying) and high degree of hydrolysis (80-95%). Protein content recovered from hydrolysis process is within 20-29%. Microstructure of freeze dried YSF protein hydrolysate had ‘collapsed-building’ structure (irregular shapes with edges) while spray dried had small and spherical structure. Freeze dried protein hydrolysates were significantly (p
Mas Cotek or Ficus deltoidea is regarded as one of the most precious herbal plants in Malaysia due to its content of beneficial active compounds and appreciation as a traditional remedy. This research investigated performance of aqueous or water extraction of dried Mas Cotek leaves for vitexin and isovitexin compounds using three regiments of temperatures (50, 70 and 100°C) in sample-to-water ratios of 1:10, 1:20 and 1:30g/mL during 8 hours of extraction. The optimum yield recorded for vitexin compound was 0.463 ± 0.045 (%w/w) from; 1:30 g/mL sampleto- water ratio, 50°C temperature at 4th hour of extraction. While for isovitexin compound, the optimum value recorded was 0.136 ± 0.015 (%w/w) from; 1:20 (g/mL) sample-to-water ratio, 50°C temperature at 5th hour of extraction. The morphological characterization of the extracted dried leaves particles performed using FE-SEM showed an intact and less damaged surface of extracted sample after 8 hours of extraction. The experimental values under best conditions were consistent with the predicted values, which suggested that aqueous extraction of Mas Cotek leaves is a good platform to serve as baseline study for more advanced extraction techniques.
The accurate determination of reducing ends of malto-oligosaccharides is essential for calculating the enzyme activities of starch debranching enzymes. The suitability of the 3,5-Dinitrosalicylic acid (DNS) method, the Dygert method, and the Bicinchoninic acid (BCA) method for accurate determination of reducing ends from malto-oligosaccharides of different chain lengths is compared. The results showed that BCA assay was much more accurate than the other assays. The results for the BCA assay showed that different malto-oligosaccharides gave observed (measured) values that were significantly similar to the expected (predetermined) values. In contrast, the DNS and Dygert assays underestimated the amount of reducing sugar present for glucose. Furthermore, both DNS and Dygert methods showed increasing degree of overestimation of the amount of reducing sugar present with the increasing length of the malto-oligosaccharide sugar chains. The BCA assay can suitably quantify reducing sugars even in mixtures of oligosaccharides with different chain lengths. Thus, enzyme activities can be measured without bias towards higher values for enzymes that preferentially cleave the longer chain lengths.