Baking temperature and time are among the conditions for producing good quality cakes. The aim of this study was to investigate the effects of baking temperature and time on the volume expansion, moisture content, and texture of moist cakes baked in either an air fryer or a convection oven. The cakes were baked under different conditions: (1) baking temperature of 150 °C, 160 °C, and 170 °C for both air fryer and convection oven and (2) baking time of 25, 30, 35 min for air fryer and 35, 40, 45 min for convection oven. Baking temperature and time were found to have a significant (p
The nutrient composition, cooking characteristics and sensory properties of beef patties incorporated with various level of cornsilk were studied. The beef patties were formulated with either 2, 4 or 6% of cornsilk. Protein content increased in line with the cornsilk level in both raw and cooked beef patties. Both raw and cooked patties incorporated with 6% cornsilk recorded the highest protein concentration at 17.2 and 23.3%, respectively. Both raw and cooked patties containing 6% cornsilk recorded the lowest concentration of fat at 12.4 and 11.4%, respectively. All cooked patty samples recorded moisture content ranging from 40.42-42.98%. Beef patty formulated with 6% cornsilk recorded the highest cooking yield at 80.13% compared to other treatments. The addition of cornsilk did not change the sensory properties and consumer acceptability of cornsilk-based beef patties. Cornsilk fibre was effective in improving cooking yield, moisture and fat retention and enhancing texture of beef patties.
The proximate analyses, physical traits and sensory properties of chicken patties incorporated with different levels of cornsilk dietary fibre were studied. The patties were formulated with 2%, 4% and 6% dried ground cornsilk. The protein content increased in line with the cornsilk level in both raw and cooked chicken patties. Cooked chicken patties incorporated with 6% cornsilk showed the highest protein concentration at 28.42% and the lowest fat concentration at 14.60%, respectively. All cooked patty samples recorded moisture content ranging from 42.73-46.40%. Patty formulated with 6% cornsilk recorded the highest cooking yield at 83.03%. Cornsilk fibre has been successful in improving cooking yield and in retaining moisture and fat of chicken patties. The addition of cornsilk fibre does not change the sensory properties and the acceptability of chicken patties.
A synergistic effect of the activated limestone-based catalyst (LBC) and microwave irradiation on the transesterification of waste cooking oil (WCO) was screened using a two-level factorial design and response surface methodology. The catalyst was prepared using a wet-impregnation method and was characterised for its surface element, surface morphology, surface area and porosity. The reaction was performed in a purpose-built continuous microwave assisted reactor (CMAR), while the conversion and yield of biodiesel were measured using a gas chromatography. The results showed that the catalyst loading, methanol to oil molar ratio and the reaction time significantly affect the WCO conversion. The optimum conversion of oil to biodiesel up to 96.65% was achieved at catalyst loading of 5.47 wt%, methanol to oil molar ratio of 12.21:1 and the reaction time of 55.26 min. The application of CMAR in this work reduced the transesterification time by about 77% compared to the reaction time needed for a conventional reactor. The biodiesel produced in this work met the specification of American Society for Testing and Materials (ASTM D6751). Engine test results shows the biodiesel has a lower NOx and particulate matters emissions compared to petrodiesel.
Hydrothermal carbonization (HTC) provides alternatives technique to produce a nanosize activated carbon from biomass with a high surface area. Herein, this study we prepared empty fruit bunch-based activated carbon (EFBHAC) using HTC technique. The activated carbon was then functionalized with K2CO3 and Cu(NO3)2 to produce bifunctional nano-catalyst for simultaneous esterification-transesterification of waste cooking oil (WCO). The physicochemical properties were performed i.e. N2 sorptions analysis, TPD-CO2/NH3, FESEM, EDX, FTIR and XRD analysis. The results revealed that produced EFBHAC possessed a BET surface area of 4056.17 m2 g-1, with pore volume of 0.827 cm3 g-1 and 5.42 nm of pore diameter resulting from hydrolysis, dehydration decarboxylation, aromatization and re-condensation during HTC process. Impregnation of EFBHAC with K2CO3 and Cu(NO3)2 granted a high amount of basicity and acidity of 9.21 mmol g-1 and 31.41 mmol g-1, respectively, accountable to high biodiesel yield of 97.1%, produced at the optimum condition of 5 wt% of catalyst loading, 12:1 of methanol to oil molar ratio at 70 °C for 2 h. More than 80% of biodiesel was produced after the 5th cycle depicted the good reusability. The transformations from WCO to biodiesel was confirmed via 1H NMR, FTIR and TGA analysis. Fuel properties revealed kinematic viscosity of 3.3 mm2 s-1, cetane number of 51, flash point of 160.5 °C, cloud and pour point of 11 °C and -3 °C, respectively. These results show the excellent potential of waste materials to prepare bifunctional nano-catalysts to produce higher biodiesel yield which has potential to be commercialized.
The ageing of the bitumen during storage, mixing, transport and laying on the road, as well as in service life, are the most important problems presented by the use of bitumen in pavements. This paper investigates the possibility of using waste cooking oil (WCO), which is a waste material that pollutes landfills and rivers, as an alternative natural rejuvenating agent for aged bitumen to a condition that resembles the original bitumen. With this target, the physical and chemical properties of the original bitumen, aged bitumen and rejuvenated bitumen were measured and compared by the bitumen binder tests - softening point, penetration, Brookfield viscosity, dynamic shear rheometer and Fourier transform infrared spectroscopy. In addition, the behaviour of the WCO rejuvenated bitumen is investigated and compared with virgin bitumen after using the rolling thin film oven ageing process. In general, the results showed that using 3-4% of WCO the aged bitumen group 40/50 was rejuvenated to a condition that closely resembled the physical, rheological properties of the original bitumen (80/100), however, there was a difference in the tendency to ageing between the WCO rejuvenated bitumen and the virgin bitumen during mixing, transport and laying on the road.
Acrylamide is a probable human carcinogen, and its presence in a range of fried and oven-cooked foods has raised considerable health concern world-wide. Dietary intake studies observed significant variations in acrylamide concentrations, which complicate risk assessment and the establishment of effective control measures. The objective of this study was to obtain an insight into the actual variation in acrylamide concentrations in French fries prepared under typical conditions in a food service establishment (FSE). Besides acrylamide, frying time, frying temperature, and reducing sugars were measured and the actual practices at receiving, thawing and frying during French fries preparation were observed and recorded. The variation in the actual frying temperature contributed most to the variation in acrylamide concentrations, followed by the variation in actual frying time; no obvious effect of reducing sugars was found. The lack of standardised control of frying temperature and frying time (due to inadequate frying equipment) and the variable practices of food handlers seem to contribute most to the large variation and high acrylamide concentrations in French fries prepared in a restaurant type of FSE as compared to chain fast-food services, and institutional caterers. The obtained insights in this study can be used to develop dedicated control measures in FSE, which may contribute to a sustainable reduction in the acrylamide intake.
BACKGROUND:
The effect of preparation methods (raw, half-boiled and hard-boiled) on protein and amino acid contents, as well as the protein quality (amino acid score) of regular, kampung and nutrient enriched Malaysian eggs was investigated.
METHODS:
The protein content was determined using a semi-micro Kjeldahl method whereas the amino acid composition was determined using HPLC.
RESULTS:
The protein content of raw regular, kampung and nutrient enriched eggs were 49.9 ±0.2%, 55.8 ±0.2% and 56.5 ±0.5%, respectively. The protein content of hard-boiled eggs of regular, kampung and nutrient enriched eggs was 56.8 ±0.1%, 54.7 ±0.1%, and 53.7 ±0.5%, while that for half-boiled eggs of regular, kampung and nutrient enriched eggs was 54.7 ±0.6%, 53.4 ±0.4%, and 55.1 ±0.7%, respectively. There were significant differences (p < 0.05) in protein and amino acid contents of half-boiled, hard-boiled as compared with raw samples, and valine was found as the limiting amino acid. It was found that there were significant differences (p < 0.05) of total amino score in regular, kampung and nutrient enriched eggs after heat treatments.Furthermore, hard-boiling (100°C) for 10 minutes and half-boiling (100°C) for 5 minutes affects the total amino score, which in turn alter the protein quality of the egg.
Heterocyclic amines (HCAs) are carcinogenic food toxicants formed in cooked meats, which may increase the risk of cancer development in humans. Therefore, in this study, the effect of stingless bee honey from different botanical origins on the formation of HCAs in grilled beef satay was investigated. HCAs concentration in grilled beef satay was determined by using high performance liquid chromatography (HPLC). In total, six of the most toxigenic HCAs representing aminoimidazo-azaarenes (AIAs) (MeIQx, 4,8-DiMeIQx, and PhIP) and amino carbolines (norharman, harman, and AαC) groups were identified in all the beef samples investigated. A significant reduction in HCAs was observed in grilled beef marinated in honey as compared to beef samples marinated in table sugar (control), in which the reduction of 95.14%, 88.45%, 85.65%, and 57.22% was observed in gelam, starfruit, acacia, and Apis honey marinades, respectively. According to the partial least squares regression (PLS) model, the inhibition of HCAs in grilled beef was shown to be significantly correlated to the antioxidant activity (IC50) of the honey samples. Therefore, the results of this study revealed that the addition of stingless bee honey could play an important role in reducing HCAs in grilled beef.
Elderly are exposed to physical impairment. This has a strong impact on their daily activities including
frying, which is one of the most popular cuisine preparations. The stove height and work envelope
are two major ergonomic issues in performing cooking task. There has been little research focusing
on Malaysian elderly task performing in addressing these issues. The objectives of this study were to
identify the acceptable stove height and depth and to determine the working envelope among Malaysian
elderly using anthropometric data. A total of 55 Malaysian elderly (25 male and 30 female) aged between
60 to 85 years participated in this study. Five body measurements were taken from each subject using
an anthropometer. The measurements are stature height, shoulder height, arm span, arm reach forward
and waist height. Apart from these anthropometric measurements, their present stove height was also
measured. The acquisition of stove height dimensions was performed through a series of door to door
visit of the elderly homes in Kg. Sg. Merab. These variables were used to estimate the elderly working
envelope and determine the stove height, width and depth. Data were analysed using SPSS software. The
waist height dimension was to estimate the stove height, the arm reach forward for the depth and the arm
span for the length of the table-top where the stove was placed. Meanwhile the stature and shoulder height
were used for estimating the position of the overhead compartment or placement of cooking utensils.
The 5
th
percentile was chosen since it is appropriate to accommodate 90% of the studied population. The 5
th
percentile was also applied for the setting
of the working envelope so as to provide better
reaching tolerances. Meanwhile, standard was used
to compare the present state of the studied kitchen
setting. The results show that 56.4% of the elderly
waist height is lower than the standard table-top
height which is 36 inches (91.4cm) and 36.4% of the stove height was found higher than that of the standard. This could apparently cause fatigue and
discomfort to shoulders, the neck, the arm and the back of the user. Anthropometrics measurements can
be used for estimating the stove height, length and depth. These could also calculate a space taken for
certain physical activities, such as frying task envelope. Providing a good combination of stove height,
length, depth and ergonomic working envelope could hopefully improve the elderly cooking task and
increase their quality of life.
Matched MeSH terms: Cooking; Cooking and Eating Utensils
Total polar compounds (TPC) and free fatty acids (FFA) are important indicators in evaluating the quality of frying oil. Conventional methods to determine TPC and FFA are often time consuming, involved laboratory analyses which required skilled personnel and used substantial amount of harmful solvent. In this study, dielectric spectroscopy technique was used to investigate the relation between dielectric property of refined, bleached and deodorized palm olein (RBDPO) during deep frying with TPC and FFA. In total, 150 batches of French fries were intermittently fried at 185 ± 5 °C for 7 hr a day over 5 consecutive days. A total of 30 frying oil samples were collected. The dielectric property of frying oil samples were measured using impedance analyzer with frequencies ranging from 100 Hz to 10 MHz. The TPC of frying oil samples were measured with a Testo 270, while the FFA analysis was done using Malaysian Palm Oil Board (MPOB) test method. Results showed that dielectric constant, TPC and FFA of RBDPO increased as the frying time increased. Dielectric constant increased from 3.09 to 3.17, while TPC and FFA increased from 9.96 to 19.52 and from 0.08% to 0.36%, respectively. Partial least square (PLS) analysis produced good prediction of TPC and FFA with the application of genetic algorithm (GA). Model developed for prediction of TPC and FFA yielded highly significant correlation with R2 of 0.91 and 0.95, respectively and both had root mean square error in cross-validation (RMSECV) of 1.06%. This study demonstrates the potential of dielectric spectroscopy in monitoring palm olein degradation during frying. PRACTICAL APPLICATION: The application of dielectric spectroscopy to detect degradation of palm olein during frying was studied. The dielectric property of palm olein during frying has successfully correlated with TPC and FFA. The model developed in this study could be used for the development of a sensing system for palm olein degradation monitoring.
Red palm olein is known to be high in carotenes and vitamin E (tocols) and possess various nutritional benefits. This study evaluates the effect of prolonged heating using three common cooking techniques i.e. deep-fat fryer, microwave oven and conventional oven, on the profiles of carotenes and tocols as well as the physico-chemical changes occurring in red palm olein when compared to conventional palm olein. Physico-chemical changes in all oils were gauged based on their peroxide, p-anisidine and total oxidation values, acidity, and fatty acid composition. Both red palm olein and palm olein were thermally stable based on their lower rate of hydrolytic and oxidative degradations as well as higher tocols retention, which allow the oils to undergo heating up to 3 hours using deep-fat fryer and conventional oven. Nevertheless, red palm olein seemed not suitable for prolonged heating processes considering lower retention of carotenes. Microwave heating also influenced the stability of phytonutrients.
The objective of the study was to determine the effect of different types of soy sauce and marinating time on the formation of heterocyclic amines (HCAs) in roasted chicken. Chicken breast samples were marinated with sweet, salty, light and dark soy sauce at 0, 3, 6 and 12 h (control treatment was the chicken without marinade). The concentrations of free amino acids, sugars and creatinine were determined before roasting while HCA concentrations were determined after roasting. All types of soy sauce significantly increased (p ≤ 0.05) the concentration of HCAs in roasted chicken with increasing marinating time. The highest increment of total concentration of HCAs was found in samples marinated with light soy sauce (887%) followed by dark (375%), salty (193%) and sweet (169%) at 12 h. PhIP (2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine) showed a substantial reduction in samples only momentarily marinated with sweet, salty and dark soy sauce (0 h). Free amino acids were found to be more strongly correlated with the formation of HCAs than reducing sugars or creatinine.
This work investigated the underlying formation of acrylamide from amino acids in frying oils during high temperatures and at different times via modeling systems. Eighteen amino acids were used in order to determine which one was more effective on acrylamide production. Significantly the highest amount of acrylamide was produced from asparagine (5987.5µg/kg) and the lowest from phenylalanine (9.25µg/kg). A constant amount of asparagine and glutamine in palm olein and soy bean oils was heated up in modelling system at different temperatures (160, 180 and 200°C) and times (1.5, 3, 4.5, 6, 7.5min). The highest amount of acrylamide was found at 200°C for 7.5min (9317 and 8511µg/kg) and lowest at 160°C for 1.5min (156 and 254µg/kg) in both frying oils and both amino acids. Direct correlations have been found between time (R2=0.884), temperature (R2=0.951) and amount of acrylamide formation, both at p<0.05.
Changes of aroma constituents of palm olein and selected oils after frying French fries have been studied. The aroma constituents of used oils were collected using a solid-phase microextraction (SPME) headspace technique with an absorbent of a divinylbenzene/carboxen (DVB/CAR) (50/30 microm) on polydimethylsiloxane (PDMS) fibre. The extracted volatiles were desorbed from the fibre in the injection port of the gas chromatograph at 250 degrees C and the aroma constituents were identified by GC-MS. Analytical data showed that volatile constituents of palm olein, soybean oil, corn oil and sunflower oil changed while frying continued from 2 to 40 h, respectively. In palm olein, the 2t,4t-decadienal content decreased from 14.7 to 5.5 microg g(-1) (40 h) whilst hexanal increased from 7.9 microg g(-1) (2 h) to 29.2 microg g(-1) (40 h), respectively. Similar result was also obtained from soybean oil after frying French fries. The 2t,4t-decadienal content decreased from 15.9 microg g(-1) (2 h) to 3.2 microg g(-1) after 40 h frying whilst hexanal increased from 10.2 microg g(-1) (2 h) to 34.2 microg g(-1) (40 h). Meanwhile, in corn oil, it was found that 2t,4t-decadienal decreased from 15.6 microg g(-1) (2 h) to 3.2 microg g(-1) (40 h) whilst hexanal increased from 11.3 microg g(-1) (2 h) to 33.8 microg g(-1) when frying time reached 40 h. In sunflower oil, it was found that 2t,4t-decadienal, decreased from 16.8 microg g(-1) (2 h) to 1.2 microg g(-1) (40 h) while hexanal increased from 9.5 microg g(-1) (2 h) to 32.4 microg g(-1) when frying time reached 40 h. It also showed that used oils exhibited off-odour characteristics due to the increasing amount ofhexanal while their freshness characteristics diminished due to the decreasing amount of 2t, 4t-decadienal.
The present work deals with the production of paper materials from onion peels (Allium Cepa) fibers
as an alternative potential non-wood fiber. The onion peels were obtained from a local small and
medium food industry. The onion peels were cooked at 120, 150 and 180 minutes. The peels were
grinded and poured in a set of mould and deckle for the formation of a thin sheet of paper. The
physical, mechanical, morphological characteristics and water rise capillary values (KLEMM
Method) were evaluated to determine its suitability for a paper material. The results show that the
increase in cooking time from 120 to 180 minutes resulted in an increase in the tensile index from
32.28N*m/g to 42.13N*m/g and tear index from 9.80mN*m2
/g to 15.62mN*m2
/g. The bonding
strength increased due to higher number of fibers, finer fiber size, and increase in the fiber contact
area and fiber distribution. The high porosity area affects the performance of water rise capillary
values of the paper sheets. The onion peels fiber gave impressive handsheets characteristics when
compared with other sources of non-wood fibers.
Soy-based products are one of famous raw ingredients used in the preparation of Asian cuisines. These soy-based products are good source of isoflavones. This study was carried out to observe the effects of different cooking methods on isoflavone content in soy-based products. A total of eight Malaysian dishes prepared using soy-based products with different cooking methods was selected as samples for this study. Daidzein and genestein contents in raw and cooked soy-based products were both quantified using high performance liquid chromatography (HPLC). The results showed that dishes containing tempe as ingredients had significantly higher (p<0.05) amount of isoflavone content, in both raw and cooked forms, as compared to those prepared from other types of soy-based products when based on dry and wet. In conclusion, the isoflavone content was significantly reduced (p<0.05) in some cooked soy-based products (tempe (TSS and ML), fu jook (ML) and firm tofu (FTC)) based on dry weight as compared with the raw ones. However, the correlations between isoflavone content with cooking methods, durations and temperatures were not significant (p>0.05) in this study.
This study was conducted to identify the practices of Malay chefs in preparing traditional Malay dishes at hotels in the Klang Valley. In addition, this study aimed to identify the level of knowledge and practices of these chefs with regard to traditional cooking and to analyse how the knowledge could be passed on to the younger generation of Malay chefs. In reality, these practices and traditions which include the practices in food preparation, skills and cooking techniques to maintain the authenticity and sustainability of the traditional Malay cuisine are slowly being neglected, especially among those in the hotel industry. The younger generation of Malay chefs no longer seems to take pride in the traditional way of cooking. In addition, the use of processed food in Malay kitchens is very common today. In order to achieve the aims of the study, a qualitative research was conducted. Chefs at various hotels in the Klang Valley were interviewed to determine their current practices. The findings showed that the techniques of cooking traditional Malay foods have been tainted with modern culinary techniques due to a lack of exposure and knowledge in traditional Malay cuisine. In general, traditional cooking methods are viewed as outdated, obsolete and not in accordance to modernisation. By conforming to the style of cooking with modern equipment and technology, this has indirectly altered the prevailing practices of the traditional food preparation in hotels.
Bacillus cereus (B. cereus) isolates are toxigenic and can cause food poisoning. Cooked rice is
a potentially hazardous food, especially in tropical countries. The aim of this study was to determine the prevalence of B. cereus and B. thuringiensis in raw and cooked rice marketed in Selangor, Malaysia. In this research combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) was used to detect gyrB gene in B. cereus and B. thuringiensis. Five local varieties of raw rice samples were negative for B. thuringiensis but all (100%) were positive for B. cereus. A total of 115 cooked rice samples (nasi lemak, nasi briyani, nasi ayam and nasi putih) were studied for the presence of B. cereus and B. thuringiensis. Nasi ayam was found to have the highest prevalence (100%) of B. cereus compared to nasi putih (76.2%) and nasi lemak (70.4%). Nasi briyani had the lowest prevalence (50%) of B. cereus. The frequencies of B. thuringiensis were found to be 10, 30 and 35.2 % in nasi putih and nasi ayam, nasi briyani and nasi lemak, respectively. The range of B. cereus and B. thuringiensis in the samples was from < 3 to 1100 MPN/g in different samples. Maximum number of B. cereus was observed in nasi lemak, nasi briyani and nasi putih ( > 1100 MPN/g) while nasi ayam showed less contamination (460 MPN/g) with B. cereus which was significantly different (P < 0.05 ) from others. The number of B. thuringiensis in nasi lemak, nasi briyani, nasi putih and nasi ayam were found to be >1100, 93, 9.2 and 3.6 MPN/g, respectively.
In the present study, six different rice varieties marketed in Penang, Malaysia (locally grown and imported) were evaluated for proximate composition, physiochemical properties and cooking qualities. Overall, 'Black rice' variety had the highest protein content (8.16%) with lowest fat content (0.07%). Between the various rice varieties investigated, thousand kernel weight varied between 16.97-19.43 g, length/breadth (l/b) ratio was between 2.09-3.75, while bulk density varied between 0.81-0.86 g/ml. Amylose content was highest (27.71%) in white rice (local, medium grain type) with lowest recorded for brown rice variety (3.36%). Results on minimum cooking time showed it to range between 10 to 31.67 minutes with the brown rice cooking the slowest. The water uptake ratio ranged between 2.33 to 3.95 and was low in glutinous rice (2.33), while gruel solid loss (range from 3.17 to 6.43) was lowest in Basmati rice variety (3.17%). The minimum cooking time was found to be negatively correlated with amylose content (r = -0.97). A positive correlation was recorded for both amylose content and l/b ratio in relation to elongation of cooked rice. These results highlight cooking and physiochemical properties of rice to be strongly dependent on their amylose content. Results generated in this study might be able to provide vital information's on identifying 'superior quality of rice' marketed in Penang, based on their proximate composition as well as on their physiochemical and cooking properties.