Assessment of Heavy Metals in Mukunuwenna (Alternanthera Sessilis) Collected from Production and Market Sites in and Around Colombo District,Sri Lanka

The present study was conducted to evaluate the levels of trace metals (Ni, Cd, Cr, Pb and Cu) in Mukunuwenna (Alternanthera sessilis) samples randomly collected from the production and market sites located in and around Colombo District, Sri Lanka, using the Atomic Absorption Spectrophotometry. Significant differences in heavy metal concentrations were observed between both the production sites and market sites (P<0.05). Heavy metal accumulations in Mukunuwenna tested were higher at the market sites than at the crop production sites. The average concentrations (mg kg^-1) of heavy metals in Mukunuwenna samples collected from the production sites were estimated as Ni (6.48±6.74), Cd (0.20±0.11), Cr (3.36±2.76), Pb (2.96±2.16) and Cu (11.85±7.51). The mean concentrations (mg kg^-1) of Ni, Cd, Cr, Pb and Cu in Mukunuwenna samples collected from different marketing sites were reported as 7.90±5.98, 0.25±0.18, 4.09±3.36, 3.63±3.65, 13.05±5.15 respectively. The highest contaminated field and market samples were reported from the Kolonnawa area. The samples collected from the market sites were subjected to three processing treatments (raw, cooked and stir-fried) and analyzed for heavy metals, in order to find out the effect of food processing techniques on reducing the heavy metal contaminations of Mukunuwenna samples. The average levels (mg kg^-1) of metals detected in raw, cooked and stir-fried Mukunuwenna samples were as follows: Ni (2.20±1.04, 1.77±0.84, 1.46±1.03), Cd (0.19±0.11, 0.12±0.07, 0.10±0.06), Cr (2.37±1.58, 2.27±1.57, 2.20±1.54), Pb (0.26±0.39, 0.22±0.34, 0.21±0.34) and Cu (9.59±4.48, 8.29±3.35, 7.45±3.72). The results showed no significant differences in heavy metal contents among three processing methods (P<0.05). Therefore, the type of processing method has a minimal effect on reducing the heavy metal contents of Mukunuwenna samples.     

Effects of temperature on the physicochemical properties of starches extracted from microtubers grown from different potato cultivars

Twelve potato cultivars were grown as microtubers in constant environment chambers at two temperatures in total darkness for 28 days. For starch extracted from microtubers grown at 12 or 22 °C, the amylose content ranged from 25.0 to 29.0% (average 27.3 ± 1.4%) or 29.5 to 32.7% (average 30.9 ± 1.4%), the amylose/amylopectin ratio from 1:2.5 to 1:3.0 (average 1:2.7) or 1:2.1 to 1:2.4 (average 1:2.2) and the phosphorus content from 0.41 to 0.93 g kg⁻¹ (average 0.72 g kg⁻¹) or 0.38 to 1.67 g kg⁻¹ (average 0.97 g kg⁻¹) respectively. Two major fractions (F1 and F2) were obtained for isoamylase‐debranched starch (amylopectin), with the chain length (CL) averaging 56 ± 3 or 55 ± 1 for F1 and 20 ± 1 or 21 ± 1 for F2 from 12 or 22 °C growth temperature respectively. Peak gelatinisation temperature (T_p) and enthalpy (ΔH) were influenced strongly by growth temperature, with T_p ranging from 60.8 to 64.5 °C (average 62.1 ± 1.0 °C) or 66.9 to 69.6 °C (average 68.2 ± 0.9 °C) and ΔH from 13.3 to 16.9 J g⁻¹ (average 14.8 ± 1.0 J g⁻¹) or 11.3 to 19.5 J g⁻¹ (average 16.3 ± 2.4 J g⁻¹) from 12 or 22 °C growth temperature respectively. The collective data generated at 12 °C were generally more comparable to data published elsewhere (but discussed in the text) for the same potato cultivars grown in field plots (Perthshire). However, there were cultivar specific responses to field or constant environment chambers which make direct comparisons between starches produced from the two systems subject to some variation. Copyright © 2004 Society of Chemical Industry     

Inactivation Kinetics of Enzymes by Using Continuous Treatment with Microbubbles of Supercritical Carbon Dioxide

ABSTRACT Enzyme inactivation using a new apparatus for continuous treatment with microbubbles supercritical carbon dioxide (SC-CO₂) was investigated. D value of a-amylase (5.0±1.2 min) subjected to microbubbles of SC-CO₂ treatment (microbubbles-SCT) at 35 °C, 30 MPa was lower than that (227 ± 15.9 min) subjected to heat treatment (HT) at 70 °C. D value of acid protease was reduced by microbubbles-SCT at 50 °C, 30 MPa (15.4 ± 4.1 min), compared to HT at 50 °C (233 ± 15.2 min). The activation energy for the inactivation of acid protease (135 ± 8.3 kJ mol^-1) by microbubbles-SCT was 1 half of that (259 ± 9.0 kJ mol^-1) by HT. These results indicated that continuous treatment with microbubbles of SC-CO₂ was effective for enzyme inactivation.     

The levels of S-alk(en)yl-L-cysteine sulphoxides during the growth of the onion (Allium cepa l.)

Flavour precursors, the S-alk(en)yl-L -cysteine sulphoxides, change considerably in both concentration and total amount during the growth of onions. For the brown onion cv. Pukekohe Long Keeper (PLK) and for the white onion cv. Dehyso, (±)-S-1-propyl-L -cysteine sulphoxide (±PCSO) is the predominant flavour precursor, with (±)-trans-S-1-propenyl-L -cysteine sulphoxide (±PECSO) and (±)-S-1-methyl-L -cysteine sulphoxide (±MCSO) in a minor role. For PLK the greatest concentration of all three precursors is just prior to bulbing (3.6±1.1 mg g^?1 fresh weight); for Dehyso the greatest concentration is at bulbing (4.6±0.6 mg g^?1 fresh weight); Both varieties show a mid-season reduction in flavour precursor concentration (of about 45%), followed by a small but significant increase in ±PCSO concentration during the end of season leaf die-down. The total amount of the three flavour precursors per bulb in both varieties shows a maximum in late January (360±107 mg for PLK, 602±144 mg for Dehyso). In the subsequent months there is a dramatic reduction in the total amount of ±PECSO and ±MCSO, and a slight reduction in ±PCSO. Both varieties show an increase in the amount of ±PCSO at leaf die-down. The relative proportions of these flavour precursors change with bulb age and cultivar. These results suggest that white onions used for drying and processing could be harvested from bulbing onwards. Furthermore, when onion cultivars and onion plant selections are assessed for flavour, care needs to be given to the stage of maturity of the onion.     

Energy and protein requirements of crossbred (Holstein × Gyr) growing bulls

The objective of this study was to estimate the energy and protein requirements of crossbred (Holstein × Gyr) growing bulls. Twenty-four 10-mo-old bulls [initial body weight (BW) = 184 ± 23.4 kg] were used in a comparative slaughter trial. Six bulls were slaughtered at the beginning of the experiment as the reference group, to estimate initial empty body weight (EBW) and energy and protein contents of the remaining animals. The remaining bulls were assigned to a completely randomized design with 3 levels of dry matter intake and 6 replicates. The levels of dry matter intake were 1.2% of BW, 1.8% of BW, and ad libitum to target orts equal to 5% of the total amount that was fed. The remaining bulls were slaughtered at the end of the experiment. The bulls were fed a diet consisting of 59.6% corn silage and 40.4% concentrate on a dry matter basis. The equation that determined the relationship between EBW and BW was EBW = (0.861 ± 0.0031) × BW. The relationship between empty body gain (EBG) and average daily gain (ADG) was demonstrated by the following equation: EBG = (0.934 ± 0.0111) × ADG. Net energy for maintenance (NE_M) was 74.8 ± 2.89 kcal/kg of EBW^0.75 per day, and metabolizable energy for maintenance (ME_M) was 120.8 kcal/kg of EBW^0.75 per day. The detected efficiency of use of metabolizable energy for maintenance (k_m) was 61.9%. The equation used to estimate net energy for gain (NE_G) was as follows: NE_G = (0.049 ± 0.0011) × EBW^0.75 × EBG^{0.729 ± 0.0532}. The efficiency of use of metabolizable energy for gain (k_g) was 35.7%. The metabolizable protein for maintenance (MP_M) was 3.05 g/kg of BW^0.75. The equation used to estimate net protein requirements for gain (NP_G) = (87.138 ± 65.1378 × EBG) + [(40.436 ± 21.3640) × NE_G]. The efficiency of use of metabolizable protein for gain (k) was 35.7%. We concluded that the estimates of energy and protein requirements presented herein are more appropriate than the National Research Council dairy cattle model and the Brazilian BR-CORTE system to balance the diets of crossbred (Holstein × Gyr) growing bulls.     

Aflatoxins and their Metabolites in the Tissues,Faeces and Urine from Lambs Feeding on an Aflatoxin-Contaminated Diet

Twenty-four lambs were intoxicated with 2·5 mg of aflatoxin (AF) kg^-1 in their feed for 21 days. Twelve lambs were slaughtered at day 21 and the remaining animals had an 8 day clearance period. Aflatoxins and their metabolites were detected in liver, kidneys, faeces and urine using TLC and fluorescence densitometry. During the intoxication period, the samples gave a wide range of concentrations, the lower extreme being in the liver and the kidney (0·03 μg kg^-1 of AFG₁) and the higher extreme in faeces (61·82 μg kg^-1 of AFM₁) and urine (27·84 μg litre^-1 of AFM₁). The average value of AFB₁ (1·94±0·9 μg kg^-1) was higher than AFM₁ (0·35±0·17 μg kg^-1) in the liver. In the kidney AFM₁ (5·45±4·01 μg kg^-1) was higher than AFB₁ (1·29±0·84 μg kg^-1). There were higher concentrations of AFM₁ (27·2±16·1 μg kg^-1, 7·37±6·53 μg litre^-1, respectively, of average level) in faeces and urine, than of AFB₁ (17·25±8·1 and 1·78±1·57 μg litre^-1, respectively). AFB_2a appeared in the kidney (0·05±0·03 μg kg^-1) and urine (0·35±0·25 μg litre^-1). The clearance time of AFB₁ from the faeces was less than or equal to 8 days and in all samples aflatoxin residues were still detected on the 8th day of the clearance period although in low quantities. These results suggest that aflatoxin transfer to and elimination by the liver and the renal tissue is small and that the danger to humans consuming lamb meat is also small. The examination of the faeces and urine could be useful as markers to detect lambs consuming a contaminated diet. © 1997 SCI.     

A comparative investigation of the packing and flow properties of sweet potato (Ipomoea batatas) starches and their potential use in solid dosage formulations

A comparative evaluation of the flow and packing properties of starch products extracted from three sweet potato (Ipomoea batatas) cultivars grown in Jamaica was done with a view to assessing their suitability as excipients in solid dosage formulations. Significant differences were observed in the properties of the starches obtained from the different sweet potato cultivars (p<0.05). The mean granular diameter ranged from 13.4 ± 0.42 (Eustace) to 20 ± 0.85 µm (Clarendon). Clarendon starch was found to be the least cohesive and bulkiest with Compressibility Index (CI) of 32.69 ± 0.28%, angle of internal flow (θ_i) of 12.70 ± 0.12° and maximum volume reduction (a) of 35.65 ± 1.02%, while Eustace was the most cohesive and least bulky with CI values of 37.74 ± 1.06%, θ_i of 19.68 ± 0.22°, and a of 43.60 ± 0.95%. The starch powders had similar bulk densities and packing fraction (p>0.05). All other fundamental properties calculated from the projected mean diameter including surface mean diameter (d_vs), Heywood equivalent diameter (de) and specific surface (S_w) varied significantly (p<0.05) in a cultivar‐dependent manner but with no consistent pattern of variation among cultivars. The results indicate intravarietal variations in the packing and cohesive properties of the starches studied which may be a result of variations in the fundamental properties of the granules. These differences in properties may prove significant when predicting the behaviour of starches during handling and pharmaceutical formulations.     

The yield and carcass chemical composition of impala (Aepyceros melampus), a southern African antelope species

This investigation analyses the commercial carcass yields and chemical composition of impala (Aepyceros melampus). The potential of this species for the export market is also discussed. Impala rams (eight) and ewes (eight) cropped commercially in Zimbabwe were found to have a similar dressout proportion (580 g kg⁻¹), although the males had a heavier live weight (49.4 ± 4.606 kg) than the females (33.5 ± 3.417 kg). Sexual dimorphism was shown, with the males having significantly (p < 0.01) heavier necks (69 ± 5.47 g kg⁻¹) and forequarters (279 ± 3.79 g kg⁻¹) than the females (51 ± 1.70 and 259 ± 2.15 g kg⁻¹ respectively) when expressed as a proportion of cold carcass weight (27.6 ± 2.551 and 19.0 ± 1.960 kg for males and females respectively). No sexual effects (p > 0.2) were found in the mean chemical proximate composition of the 9‐10‐11 rib cut for the moisture (724.0 ± 14.00 g kg⁻¹ pooled sample), protein (238.3 ± 7.46 g kg⁻¹ pooled sample) and ash (21.2 ± 3.74 g kg⁻¹ pooled sample) contents. The females had a statistically higher (p = 0.0197) mean total lipid content (33.9 ± 1.705 g kg⁻¹) than the males (24.5 ± 3.171 g kg⁻¹). This investigation occurred at the end of the impala rut season, a period when the rams not only consume less feed but also expend more energy owing to strenuous activities in fighting for and maintaining a harem. © 2000 Society of Chemical Industry     

Evaluation of table olive by‐product as a source of natural antioxidants

The main by‐product from the table olive canning industry is the stone with some residual olive flesh. The purpose of this study was to evaluate the composition – phenolic compounds (hydroxytyrosol, tyrosol and oleuropein) and tocopherol – and the antioxidant activity in different fractions (flesh, stone and seed) from the table olive by‐product and the whole by‐product. The highest amounts of phenolic compounds (1710.0 ± 33.8 mg kg^?1) as well as the highest antioxidant activity (8226.9 ± 9.9 hydroxytyrosol equivalents mg kg^?1) were obtained in the seed. The highest amounts of hydroxytyrosol (854.8 ± 66.0 mg kg^?1) and tyrosol (423.6 ± 56.9 mg kg^?1) were found in the whole by‐product from the pepper stuffed olives, while the stone without seed had the maximum oleuropein content (750.2 ± 85.3 mg kg^?1). α‐Tocopherol values were between 79.8 ± 20.8 mg kg^?1 in the seed of the olive stone and 6.2 ± 1.2 mg kg^?1 in the whole by‐product from the anchovy‐stuffed olives. In light of the results obtained, it would seem possible to use table olive by‐product as a source of natural antioxidants in foods, cosmetics or pharmaceutical products, thus contributing to diminishing the environmental impact of table olive by‐product and to its revalorisation.     

An Investigation into the Lipid Classes of Skipjack Tuna (Katsuwonus pelamis)

The lipid classes of the muscle of Skipjack tuna (Katsuwonus pelamis) were investigated over a period of 10 months by thinlayer chromatography. Triglycerides, diglycerides, monoglycerides and phospholipids content varied between 48.36 ± 1.22% and 62.49 ± 3.40%; 20.04 ± 5.59 and 28.53 ± 4.50; 0.98 ± 0.20% and 4.84 ± 2.48% and 4.31 ± 0.96% and 9.26 ± 0.52%, respectively. Both triglycerides and diglycerides formed the major fractions (between 68 and 91%) of Skipjack muscle lipid. There was a good concentration of phospholipids. Free fatty acid levels were fairly low and varied between 0.62 ± 0.10% and 3.94 ± 0.31%. No levels of hydrocarbons were detected in lipid samples from May to September but fairly high levels of (14.97 ± 2.89% and 12.74 ± 2.68, respectively) were detected in November and January samples.     

Identification and quantification of anthocyanins from the grains of black rice (Oryza sativa L.) varieties

The purpose of this research was conducted to determine anthocyanin content from the grains of 10 Korean black rice varieties. Moreover, the primary constituents including protein and oil were evaluated. Anthocyanins, cyanidin-3-O-glucoside (1) and peonidin-3-O-glucoside (2), were isolated and elucidated using reversephase C₁₈ chromatography, nuclear magnetic resonance (NMR) spectroscopy, and high performance liquid chromatography (HPLC) with diode array detection and electrospray ionization/mass spectrometry (DAD-ESI/MS). Anthocyanin showed significant differences and cyanidin-3-O-glucoside (1) (52.1±6.3-1,601.0±8.5 μg/g) exhibited a markedly higher content than peonidin-3-O-glucoside (2) (ND-82.6±1.2 μg/g). Among varieties, ‘Heugjinjubyeo’ showed the highest anthocyanin (1: 1,601.0±8.5, 2: 82.6±1.2 μg/g), whereas ‘Heughyang’ was the lowest (1: 52.1±6.3 μg/g, 2: ND). Protein and oil exhibited the minor differences and their contents ranged from 10.7±0.0 to 14.1±0.1% and from 2.1±0.0 to 2.9±0.0%. Overall results suggest that anthocyanin can be a key factor in functional property of black rice and ‘Heugjinjubyeo’ may be very important source concerning nutritional value.     

Comparative study of natural carob fibre and psyllium husk in rats. Influence on some aspects of nutritional utilisation and lipidaemia

The effects of the addition of 100 g kg⁻¹ of psyllium husk (PSY), cellulose (CEL) or natural carob fibre (NCF) to a semi‐synthetic diet on fat (FD) and nitrogen (NF) digestibility coefficients, metabolic nitrogen utilisation (MNU), net nitrogen utilisation (NNU) and total serum cholesterol and triglyceride levels, were studied in male ‘Wistar’ rats. No significant differences were observed between the three fibres with respect to the weight increase of the animals or MNU. Significant differences were recorded for the FD of the NCF group (0.91±0.01) compared to the CEL group (0.95±0.01), as well as on ND (0.88±0.00 NCF group, 0.88±0.00 PSY group and 0.95±0.00 CEL group) and NNU. None of these indexes showed differences between the groups PSY and NCF. For the serum cholesterol levels, there were no significant differences between the non‐hypercholesterolaemic groups fed PSY, CEL or NCF; in those in which hypercholesterolaemia was induced (cholesterol and bile bovine 8.3 g kg⁻¹), significantly lower values were found in the NCF group (166±17 mg dl⁻¹ ) than in the PSY group (343±61 mg dl ⁻¹) and in the CEL group (386±48 mg dl⁻¹). © 1999 Society of Chemical Industry     

Inactivation of Escherichia coli Population on Fruit Surfaces Using Ultraviolet-C Light: Influence of Fruit Surface Characteristics

Ultraviolet-C (UV-C 254 nm) light is a possible alternative for chemical disinfection of fresh fruits. However, studies on the influence of surface characteristics on the kinetics of UV-C inactivation of microorganisms on fruits are limited. In this study, UV-C inactivation of generic Escherichia coli (ATCC 23716), a nonpathogenic surrogate strain for E. coli O157:H7, was inoculated onto the skin surface intact pear, pear with surface wounds, and the skin surface of intact peach. Disc shaped (0.057 m diameter?×?0.01 m height) fruit surface were exposed at room temperature to UV-C light ranging from 0 to 7.56?±?0.52 kJ/m² and microbial inactivation kinetics was determined. Maximum reductions of 3.70?±?0.125 log CFU/g were achieved for E. coli on intact pear surfaces (P?<?0.05), with lesser reduction on wounded pear (3.10?±?0.329 log CFU/g) and peach surfaces (2.91?±?0.284 log CFU/g) after 4 min UV-C exposure at 7.56 kJ/m² UV. The Weibull scale factor (α) values of UV-C inactivation for E. coli on an intact pear surface was 0.001?±?0.0007 min (0.235?±?0.001 kJ/m²), wounded pear surface, 0.003?±?0.001 min (0.240?±?0.002 kJ/m²) and peach surface, 0.004?±?0.0004 (0.241?±?0.0008 kJ/m²). The time required for a 90 % reduction in E. coli cell numbers or the reliable life time (t _R) calculated with the Weibull model for intact pear surfaces (0.019?±?0.009 min, 0.268?±?0.017 kJ/m²) was smaller than for wounded pear (0.062?±?0.013 min, 0.348?±?0.024 kJ/m²) and peach surfaces (0.074?±?0.012, 0.371?±?0.012 kJ/m²), suggesting that the wounds on pear surfaces and trichomes (100–1000 μm) on peach surfaces helped to shield and protect microorganisms from UV-C radiation. There was likely a more uniform distribution of bacterial cells onto pear surfaces due to its smaller surface roughness, spreading coefficient, and hydrophobic nature compared to peach. Fourier transform infrared spectroscopy indicate that bacterial membrane damage (phospholipids, protein secondary structures, and polysaccharides) and changes to DNA/RNA in E. coli resulted from UV-C treatment. UV-C can reduce E. coli populations on fresh fruit surfaces, but the efficacy of UV treatment is dependent upon the morphological and surface properties of the fruit and surface integrity.     

Corneoscleral junction angle in healthy eyes assessed objectively

PurposeTo introduce a fully objective method to measure corneoscleral junction (CSJ) angle and evaluate the CSJ angle in healthy eyes.MethodsCorneoscleral topography (Eye Surface Profiler, ESP) was acquired from the right eye of 105 healthy Caucasian subjects, ranging from 18 to 59 years old. From the raw anterior eye height data, the topographic limbus was automatically demarcated in 360 semi-meridians. Further, in limbal location, the CSJ angle was automatically calculated from corneoscleral height data using neighbouring auxiliary points for angle calculation. Additionally, CSJ angle was statistically analysed regionally.ResultsThe mean CSJ angle was 177.5 ± 1.1°. There is a mean difference of 7.7 ± 3.7° between the steepest (smallest) and flattest (largest) CSJ angle within the same eye. There exist statistically significant differences between temporal (178.2 ± 1.4°) and nasal (176.4 ± 1.1°) regions (paired t-test, p < 0.001), and between superior (178.1 ± 1.1°) and inferior (177.9 ± 1.1°) regions (p = 0.038). CSJ angle is correlated with limbus position (r = 0.43, p < 0.001).ConclusionCSJ angle is rotationally asymmetric. CSJ varies regionally, being the smallest (steepest) in the nasal region. Significant rough changes in CSJ angle were observed for some healthy individuals.     

Physicochemical Characterization of Lemongrass Essential Oil–Alginate Nanoemulsions: Effect of Ultrasound Processing Parameters

The formation of lemongrass oil (1 %?v/v) nanoemulsions in aqueous sodium alginate solution (1 %?w/v) containing Tween 80 (1 %?v/v) as nonionic surfactant was studied in terms of droplet size, electrical charge, viscosity, and whiteness index considering different ultrasonication times (0, 30, 60, 120, and 180 s) and amplitudes (30, 60, and 100 μm). The droplet size and size distribution of the emulsions decreased at increasing treatment time and amplitude. The minimum average droplet size observed in nanoemulsions was 4.31?±?0.18 nm with a narrow size distribution. The interface electrical charge of the coarse emulsion was ?18.0?±?2.9 mV, whereas in ultrasonicated nanoemulsions, it diminished up to ?55.8?±?6.4 mV when the sonication time was extended for 180 s. The viscosity of nanoemulsions also decreased at increasing treatment time and amplitude. Moreover, nanoemulsions became translucent after sonicating for 180 s at 30, 60, or 100 μm with whiteness indices of 28.61?±?0.17, 27.93?±?0.21, and 27.86?±?0.33, respectively. Therefore, it can be stated that ultrasound processing might be a feasible technology to produce highly translucent lemongrass oil–alginate nanoemulsions, with extremely small droplet sizes and high stability to be used as delivery systems of essential oils in food products. However, it is necessary to investigate the effect of ultrasound processing parameters on the antimicrobial potential of essential oils incorporated to nanoemulsions.     

Quantitative analysis of the S-alk(en)yl-L-cysteine sulphoxides in onion (Allium cepa L.)

Quantitative analysis of each of the S-alk(en)yl-L-cysteine sulphoxides was achieved by the following procedure. A methanol: chloroform: water extract of onion tissue was purified by electrophoresis. Alk(en)yl-L-cysteine sulphoxides were separated by thin-layer chromatography (t.l.c.) on commercial silica-gel plates and were reacted with ninhydrin, the spot intensity being measured by an integrating densitometer. The synthetic analogue (±)-S-1-butyl-L-cysteine sulphoxide was used as an internal standard in each extract. In white bulb onion (cv. Southport White Globe), (±)-S-1-propyl-L-cysteine sulphoxide is the predominant flavour precursor at a concentration of 2.9 ± 0.4 mg g^?1 fresh weight. ±-S-1-methyl-L-cysteine sulphoxide and (±) trans-S-1-propenyl-L-cysteine sulphoxide are present at the lower concentrations of 0.9 ± 0.25 mg g^?1 fresh weight and 0.6 ± 0.15 mg g^?1 fresh weight respectively. Stable n-butyl, trifluoroacetyl derivatives of standards and of the alk(en)yl-L-cysteine sulphoxides in extracts, were formed. Subsequent g.c.-m.s. enabled parent ions and fragmentation patterns to be recorded and allowed the conclusive identification of the endogenous alk(en)yl-L-cysteine sulphoxides.     

Numerical and Statistical Methodology to Analyze Microbial Spoilage of Refrigerated Solid Foods Exposed to Temperature Abuse

Numerical and statistical procedures based on pseudo-zero for the lag and first order reaction kinetics for the exponential growth phase were developed to analyze non-isothermal microbial spoilage. Arrhenius model parameters and their accuracy were estimated for a mixture of Pseudomonas fluorescens, Staphylococcus aureus andAchromobacter lwoffi growing in a seafood model. Linear regressions used with isothermal experiments generated initial values for nonlinear estimations of the frequency (K₀) and activiation energy (E_a) constants. An optimization technique was used to minimize the square difference between experimental and estimated values while parameter accuracy was assessed using a bootstrap method. E_a and In(K₀) were 109±3.4 and 48.3±1.5 kJ/mole for the exponential, and 152±4.0 and 64.4±1.7 kJ/mole for the lag phase, respectively. The Mann-Whitney-Wilcoxon rank sum test showed no significant differences between parameters generated by two different temperature profiles (5% significance level).     

A detailed study on multifaceted bioactivities of the extracts and isolated compounds from truffle Reddellomyces parvulosporus

Mushrooms and truffles are attracting attention as a new generation of biotherapeutics. In the current study, isolation, phenolic and organic acid composition, and antioxidant, cytotoxic, anticholinesterase activities of truffle Reddellomyces parvulosporus were examined. Four known compounds (brassicasterol ( 1 ), ergosterol peroxide ( 2 ), fumaric acid ( 3 ) and mannitol ( 4 )) were isolated with the combination of chromatographic techniques. Fumaric acid (54.74 ± 0.85 µg g⁻¹) was found as the major compound by HPLC-DAD. All isolated compounds were bioassayed for antioxidant, cytotoxic, anticholinesterase, anti-tyrosinase, anti-urease, anti-α-glucosidase and anti-α-amylase activities. Compound 1 indicated notable cytotoxic activity on MCF-7 (IC₅₀: 38.08 ± 0.75 µg mL⁻¹) and compound 3 on H1299 (IC₅₀: 62.37 ± 0.75 µg mL⁻¹). Also, compounds 1 (84.55 ± 1.14%) and 2 (84.90 ± 0.10%) showed higher anti-urease activity than thiourea (78.57 ± 0.22%), while compound 2 (66.31 ± 0.08%) displayed near-standard anti-BChE activity. Also, being the first to emphasise the potential of R. parvulosporus as a natural food additive, this study evidenced its medicinal importance by revealing bioactive compounds and properties.     

Thermal transition and thermo-physical properties of potato (<Emphasis Type="Italic">Solanum tuberosum L</Emphasis>.) var. Russet brown

Potatoes are an important food in many regions of the world and are commonly used in a variety of food products. Thermal transition and thermo-physical properties of potatoes are important in order to design efficient food processes and select appropriate storage conditions. In this study, we determined the thermal transitions and thermophysical properties of raw and blanched/par-fried potato for a temperature range of ??32 to 21.1 °C. Using differential scanning calorimetry, we found an initial freezing point (T_f) at ??1.8?±?0.1 °C, an onset of melting (T_m^′) at ??9.9?±?0.2 °C and an unfreezable water content (X^′_w) for maximally freeze-concentrated raw potato at 0.21 kg water/kg potato. Corresponding values for blanched/par-fried potatoes were ??0.9?±?0.1 °C, ??11.0?±?0.2 °C and 0.18 kg water/kg potato. Results show that an increase in solids content decreased T_f of both raw and blanched potatoes. We modelled the relationship between them using the Chen model. The apparent specific heat (C_app) increased around T_f to 31.7?±?1.13 kJ/kg K for raw potato and 26.7?±?0.62 kJ/kg K for blanched/par-fried potato. For frozen raw potato at ??32 °C, thermal diffusivity (α) was 0.89?±?0.01?×?10?^?6 m²/s and thermal conductivity (k), 1.82?±?0.14 W/m K, respectively. These values were higher for frozen raw potato than for the unfrozen raw potato (0.15?±?0.01?×?10?^?6 m²/s and 0.56?±?0.08 W/m K, respectively at 21.1 °C). The apparent density (ρ) of frozen raw potato (992?±?4.00 kg/m³ at ??32 °C) was less than that for unfrozen raw potato (1053?±?4.00 kg/m³ at 21.1 °C), and a similar trend was obtained for blanched/par-fried potato (993?±?2.00 kg/m³ at ??32 °C and 1188?±?7.00 kg/m³ at 21.1 °C, respectively). This study established a correlation between thermo-physical properties and temperature. Findings may be used to inform the design and optimization of freezing processes and frozen storage for potato products.     

Ultraviolet Light-Assisted Photocatalytic Disinfection of <Emphasis Type="Italic">Escherichia coli</Emphasis> and Its Effects on the Quality Attributes of White Grape Juice

Ultraviolet (UV) light-assisted titanium dioxide (TiO₂) photocatalysis is an emerging technology in food safety that utilizes TiO₂ photocatalysts to accelerate the generation of reactive oxygen species during UV illumination. In this work, we studied the use of immobilized TiO₂-SiO₂ photocatalysts illuminated with UVA radiation (350 nm; 14.8 mW/cm²) for the inactivation of Escherichia coli ATCC 25922 in white grape juice, and compared the effectiveness of the photocatalytic disinfection with respect to the quality attributes of white grape juice against those of thermal and UVC (254 nm; 19.7 mW/cm²) treated samples. To obtain a 5-log reduction of the target microorganism, treatment durations of UVA in the absence and presence of the photocatalyst were 60 and 40 min, respectively. A 5-log reduction with UVC radiation led to the loss of health-related compounds such as vitamin C, total phenolic content, and total antioxidant capacity at 92.0?±?1.1%, 19.4?±?5.6%, and 54.3?±?10.0%, respectively. However, the same level of reduction with UVA led to a loss of 74.2?±?2.3%, 7.1?±?3.6%, and 39.7?±?2.5%, and with UVA-assisted photocatalytic method resulted in a loss of 75.8?±?6.1%, 13.6?±?5.8%, and 45.6?±?4.4% of vitamin C, total phenolic content, and total anti-oxidant capacity, respectively. Given its efficacy in deactivating E. coli while retaining a relatively higher level of health-related constituents in the fruit juice compared to other common pasteurization techniques, the photocatalyst developed in this study provides a promising technology for food disinfection.