Hassan A. Al-Kahtani

Floral-type identification and quality evaluation of some honey types

Abstract Floral identification of six of the most commonly used honeys was investigated and their chemical characteristics were reported and compared with the Saudi Standards on honey. Microscopic examination confirmed the origin of the honey claimed by the manufacturer. ‘Sugar-feed’ honey was significantly (P

Survey of quality of used frying oils from restaurants

Commercial frying practices and frying conditions at 62 restaurants or fast-food outlets were investigated and the quality of their discarded frying oils was evaluated by several standard laboratory methods: total polar components (TPC), free fatty acids (%FFA), p-anisidine and peroxide values, color, viscosity, C18:2/C16:0, absorbance at 232 and 268 nm, and five quick test methods (Foodoil sensor, Oxifrit (RAU-Test), Fritest, Veri-Fry-TAM 150, and Veri-Fry-FFA 500). Frying techniques varied from primitive traditional practice at traditional shops to modern sophisticated frying procedures at some franchise restaurants. Discarded oils appeared to be heat-damaged to a varying extent according to the degree of quality control applied by the corresponding restaurants. Test methods were shown to possess different statistical correlations. Highly significant correlations were found between TPC and Foodoil sensor (c.f=0.93) and between Oxifrit and Fritest (c.f=0.94), each of which were also correlated relatively well to the TPC. Peroxide value followed by %FFA did not significantly (p<0.05) correlate with the TPC. Significant linear relationships (p⊕0.05) were found between the TPC and each of the other indicators but %FFA and peroxide value.

Stunning and animal welfare from Islamic and scientific perspectives.

The transformation of an animal into pieces fit for human consumption is a very important operation. Rather than argue about halal slaughter without stunning being inhumane or stunning being controversial from the Islamic point of view, we discuss slaughter, stunning and animal welfare considering both Islamic and animal welfare legislation requirements. With the world Muslim population close to two billion, the provision of halal meat for the Muslim community is important both ethically and economically. However, from the animal welfare standard point of view, a number of issues have been raised about halal slaughter without stunning, particularly, about stressful methods of restraint and the latency of the onset of unconsciousness. This paper sets out to, discuss the methods of stunning that are acceptable by Islamic authorities, highlight the requirements for stunning to be acceptable in Islam and suggest practical ways to improve the humanness of slaughter.

Chemical and biological evaluation of discarded frying palm oil from commercial restaurants

Abstract A chemical and biological evaluation of two frying palm oil samples (A and B) discarded by commercial restaurants is reported. The degree of deterioration of the discarded palm oil was chemically estimated by 10 ordinary laboratory methods and five quick-test methods, and the biological effects of the oil were investigated by feeding rats with standard diet containing 20% discarded palm oil for 28 days. The chemical measurements indicated a severe deterioration during frying operations, particularly in sample A, which increased liver index and induced a nonsignificant decrease in platelet aggregation when compared with sample B. Both samples reduced spleen index, but had no effects on animal growth, heart and thymus indices, or aorta prostacyclin release.

Amino acid and protein changes in tilapia and spanish mackerel after irradiation and storage

Abstract Some amino acids in tilapia decreased while some others increased when subjected to doses up to 10.0 kGy. However, 10 kGy contributed to a significant reduction in all amino acids of Spanish mackerel. Variations in amino acid contents continued during post-irradiation storage with no consistant trend of increase or decrease. SDS-PAGE of protein from both fish showed 27 bands of subunits with MW

Irradiation of dates: insect disinfestation, microbial and chemical assessments, and use of thermoluminescence technique

Abstract Irradiation of dates (Khalas variety) at 0.9 kGy was sufficient to eliminate single insect infestation ( Oryzaephilus surinamensis ) and mixed infestation ( O . surinamensis and Tribolium castaneum ), whereas 0.3 kGy was effective only in controlling single infestation. Sensory properties were not affected but irradiation contributed to some reduction in microbial counts immediately after irradiation and counts remained low till the end of 6 months storage period. All sugars were significantly reduced immediately after irradiation but they increased gradually with increasing storage time. Thermoluminescence (TL) technique was useful in discriminating between irradiated and unirradiated dates during the entire storage period but was less sensitive as far as the dose estimation is concerned.

Composition of ghee (Samn Barri's) from cow's and sheep's milk

Abstract The physical and chemical characteristics of ghee extracted from cows and sheeps milk were studied. Iodine number was lower, but saponification number was higher in sheeps ghee. 1,2-Diacylglycerides were absent in sheep ghee. The range of vitamin A was 315–376 μg/100 g and of cholesterol 252–284 mg/100 g. Fatty acid composition showed a relatively high degree of saturation (53.9–66.8%) with C16:0 (31.7–38.3%) and C18:1 (21.6–33.7) being the predominant saturated and unsaturated fatty acids, respectively.

Irradiation and storage effects on some properties of potato starch and use of thermoluminescence for identification of irradiated tubers

The effect on properties of starch isolated from Ajax and Diamant potatoes freshly harvested and irradiated immediately after harvest and after two weeks with 0.05, 0.10, 0.15, and 0.20 kGy were reported. Changes due to postirradiation storage up to six months at two different conditions (5 C, 90±2% RH and 20 C, 79±5% RH) were also studied. Swelling power (SP) slightly decreased or remained unchanged with different irradiation dose, but the effect of timing of irradiation after harvest was significant. Doses of 0.2 and 0.15 kGy significantly (p≤0.05) increased solubility, particularly at 90 C solubility temperature compared to lower doses. Decrease in viscosity with increasing dose immediately after irradiation was observed in both varieties but was more pronounced in Diamant. However, changes were dependent on variety, irradiation dose, timing of irradiation, and postirradiation storage conditions. Viscoamylograph test showed that 0.2 kGy significantly (p≤0.05) increased transmission temperature (TT) and temperature at maximum viscosity (TMV), but decreased the maximum viscosity immidiately after irradiation. The same trend was established during the post-irradiation storage time, particularly in Ajax starch, regardless of timing of irradiation or storage conditions. Thermoluminescence (TL) glow curves exhibited qualitative differences between irradiated and unirradiated tubers during the entire storage period, but dose estimation could not be determined.ResumenEl efecto en propiedades de almidón aisladas de papas Ajax y Diamant recién cosechadas y irradiadas inmediatamente después de la cosecha y después de dos semanas con 0.05, 0.10, 0.15 y 0.20 de kGt fue reportado. Cambios debidos al almacenamiento posirradiación haste los seis meses en dos condiciones diferentes (5°C, 90±2% RH y 20°C, 79±5% RH) fueron estudiados también. El poder de abultamiento (SP) se desminuyó ligeramente, o no cambió, con diferentes dosis de irradiación, pero el efecto del momento de la irradiación después de la cosecha fue significante. Dosis de 0.2 y 0.15 de kGt aumentaron considerablemente (p<−0.05) la solubilidad, particularmente a 90°C temperatura de solubilidad en comparación con dosis menores. La diminución en viscosidad con dosis creciente inmediatamente después de la irradiación fue observada en ambas variedades, pero fue más manifiesta en Diamant. Sin embargo, los cambios dependían de la variedad, dosis de irradiación, el tiempo de la irradiación y las condiciones de almacenamiento posirradiaciónes. La prueba de viscoamilógrafo mostró que 0.2 de kGt aumentó considerablemente (p<−0.05) la transmisión de temperatura (TT) y la temperatura a viscosidad máxima (TMV), pero se disminuyó la viscosidad máxima inmediatamente después de la irradiación. La misma tendencia fue establecida durante el tiempo de almacenamiento posirradiación, particularmente en el almidón de Ajax sin que importare el tiempo de irradiación o las condiciones de almacenamiento. Las curvas de encendimiento de Termoluminiscencia (TL) mostraron diferencias cualitativas entre tubérculos irradiadas y no irradiadas durante todo el tiempo de almacenamiento, pero el cálculo de dosis no podía determinarse.

A Fourier Transform Infrared Spectroscopy Method for Analysis of Palm Oil Adulterated with Lard in Pre-Fried French fries

Fourier transform infrared spectroscopy with attenuated total reflectance accessory was used to detect the presence of lard in French fries pre-fried in palm oil adulterated with lard. A Fourier transform infrared calibration model was obtained using partial least squares for prediction of lard in a blend mixture of lard and palm oil. The coefficient of determination (R2) of 0.9791 was obtained with 0.5% of detection limit. The error in calibration expressed with root mean square error of calibration was 0.979%. In addition, the error obtained during cross validation was 2.45%. A discriminant analysis test was able to distinguish between fries samples adulterated with lard and samples, which were pre-fried with palm oils. Fourier transform infrared spectroscopy is a fast and powerful technique for quantification of lard present in French fries.

Pork detection in binary meat mixtures and some commercial food products using conventional and real-time PCR techniques

Pork DNA was detected in meat mixtures using both conventional PCR and real-time PCR (RT-PCR). Thirty meat mixtures containing beef, chicken, camel, rabbit, goat and sheep with varying percentage of pork (0%, 1%, 5%, 10%, and 20%) and 75 commercial food products, were analyzed using conventional and RT-PCR to determine the presence of pork DNA. Pork DNA standard curves and cycle threshold (Ct) values were used for quantification. The detection limits for pork DNA in the mixtures were 0.22, 0.047, 0.048, 0.0000037, 0.015ng/μl respectively. Unlike conventional PCR, RT-PCR detected pork DNA in nine processed food samples [chicken sausages (2), chicken luncheon (2), turkey meat loaf, milk chocolate with soft nougat, jelly, cake, and candies] at pork DNA concentrations of 0.0001ng/μl or less.