Monitoring chemical and physical changes during thermal flavor generation   总被引：1，自引：0，他引：1  

Turner JA  Sivasundaram LR  Ottenhof MA  Farhat IA  Linforth RS  Taylor AJ 《Journal of agricultural and food chemistry》2002,50(19):5406-5411

On-line techniques were developed to monitor chemical and physical changes occurring during the heating of skim milk powder (SMP). Atmospheric pressure chemical ionization mass spectrometry (APCIMS) followed the generation and release of volatile compounds from SMP in a packed-bed reactor. Operating conditions were optimized to avoid condensation of high boiling compounds such as maltol, and the system was highly reproducible (CV < 7%). Differential scanning calorimetry (DSC) of SMP identified a potential glass transition at an onset temperature of 67.9 degrees C and a series of exothermic events that were related to different stages of the Maillard reaction. No lactose crystallization was found after heating. Using a heated stage reflectance FTIR device, spectra were obtained at different temperatures. Analysis of the data showed a correlation between the intensity ratio at wavenumbers 1017 and 1064 cm(-1) and the glass transition measured by DSC. This FTIR system was not sensitive enough to detect Maillard intermediates. Combining data from the three techniques provides a fuller picture of the physical changes during the Maillard reaction and their effects on the chemical reactions.  相似文献   

Sensitivity of Tilapia (Oreochromis mossambicus) to Clostridium botulinum toxins     

K V Lalitha  & K Gopakumar 《Aquaculture Research》2001,32(9):761-764

The sensitivity of Oreochromis mossambicus to Clostridium botulinum toxin types A–E was investigated. All five toxin types were toxic to O. mossambicus. In the case of toxin types A–D, O. mossambicus was considerably more resistant than mice and, in the case of type E toxin, fish were more sensitive. The minimum intraperitoneal (i.p.) dose of type E toxin for fish was half the minimum lethal dose for mice. The results of the study suggest that good hygiene should be maintained in fish/shrimp farms to keep contamination at a low level.  相似文献   

Notice     

N. Natarajan  P. C. Sundara Babu 《国际虫害防治杂志》2013,59(3):338-340

Abstract

The seasonal occurrence of gram pod borer, Heliothis armigera Hb. in sorghum during cropping periods was studied. The incidence of H. armigera larvae was highest between March and June, 1984. This gradually decreased between July and October, 1984 and was lowest between January and March, 1985. Larval counts were found to be higher on the cultivar CSH 5 than K‐tall. The main crop of first two cropping seasons harboured more larvae than the ratoon crops while in third cropping period there was no significant difference.  相似文献   

Influence of weather factors on sorghum earhead bug Calocoris angustatus Lethierry incidence     

N. Natarajan  P. C. Sundara Babu  S. Chelliah 《国际虫害防治杂志》2013,59(4):413-420

Abstract

Weather parameters during the same week and one, two, three or four weeks before were correlated with the population of earhead bug, Calocoris angustatus on different earhead stages of two hybrids, CSH 5 and K‐Tall, in main and ratoon crops. The weather factors in the different weeks contributing to the insect population varied with the stage of earhead, the hybrid and the nature of the crop (main or ratoon). In the main crop, the insect population at pre‐flowering, milky, dough and maturity stage was influenced by weather parameters one week before, the same, two and three weeks before respectively. Morning relative humidity was important in both hybrids at all stages, with a few exceptions. In the ratoon crop, the pre‐flowering and maturity stage populations were influenced by the weather parameters of the same week. The populations at milky and maturity stage were influenced by parameters four weeks and one week before the observations respectively. The factors influencing the population on CSH 5 and K‐Tall varied. In most cases morning relative humidity had a positive influence.  相似文献   

Studies on the sorghum grain midge,Contarinia sorghicola Coquillet,in relation to environmental influence     

K. Natarajan  S. Chelliah 《国际虫害防治杂志》2013,59(4):276-285

Abstract

Biology, ecology and damage potential of the sorghum midge, Contarinia sorghicola Coquillet, were studied at Coimbatore, India. The life cycle of the midge was shorter in summer than winter: Johnson grass, Sorghum halepense and pearl millet, Pennisetum americanum served as alternate hosts for the sorghum midge. Seasonal incidence studies revealed that four peak infestations occurred in crops sown in April, June, August and October. Midge developmental stages were quite active all through the year with no diapause, Peak adult midge attraction to the light trap was recorded at 21.00 hours. However, adult midges were found to be quite active only in the daytime in the field. There was no relationship between adult midge catches from the light trap and the population recorded in the field. Morning relative humidity and wind velocity were negatively associated with the population of midge attracted to the light trap. An increased percentage of midge population was recorded in the light trap during the new moon and second quarter phases of moon. Sticky traps were not efficient in trapping adult midges. One pair of adult midge per earhead caused 16–9% grain damage.  相似文献   

Histopathological changes in giant freshwater prawn Macrobrachium rosenbergii (de Man 1879) fed with probiotic Bacillus licheniformis upon challenge with Vibrio alginolyticus          下载免费PDF全文

Ranjit Kumar Nadella  Raman Ram Prakash  Gyanaranjan Dash  Sreenath Kannanchery Ramanathan  Lalitha Velayudhan Kuttanappilly  Mukteswar Prasad Mothadaka 《Aquaculture Research》2018,49(1):81-92

The effect of dietary supplementation of probiotic bacterium Bacillus licheniformis on the histopathological changes in Macrobrachium rosenbergii juveniles (4.0 ± 0.02 g) challenged with known pathogenic strain of Vibrio alginolyticus are reported. Two isocaloric basal diets supplemented with probiotic bacteria B. licheniformis (1.0 × 10⁹ cfu/g feed) and other without probiotic supplementation were fed to the M. rosenbergii juveniles for 45 days. The histological observations revealed no significant changes in the hepatopancreas and gut tissues of both the experimental and the control groups which indicate that the present bacterium is a safe candidate probiont for the host. Prawns were challenged with V. alginolyticus after 45 days of feeding with probiotic diet. The histopathological studies of the hepatopancreas revealed that M. rosenbergii fed with probiotic‐supplemented diet showed less changes as compared to the prawns fed with control diet on second and fourth day of post‐experimental challenge with V. alginolyticus. Histopathological observations revealed that the gills of the prawns fed with control diet were severely affected in comparison to the prawns fed with probiotic‐supplemented diet after challenging with V. alginolyticus. Results from this study revealed the improved protection by dietary incorporation of B. licheniformis in reducing the histopathological manifestations due to V. alginolyticus infection in freshwater prawn.  相似文献   

Management practices followed for draught cattle in the southern part of India   总被引：1，自引：1，他引：0  

Natarajan Akila  Mahesh Chander 《Tropical animal health and production》2010,42(2):239-245

A study was conducted to determine the management practices followed by the farmers for draught cattle in Tamil Nadu state, India. Methods of procurement of animals, use of female animals, breeds preferred, housing, health, disposal of animals, feeding, shoeing, purchase of animal-drawn implements and their maintenance were all assessed with 210 farmers from seven districts across different agro-climatic zones in Tamil Nadu. The results revealed that 86 % of the respondents purchased the draught cattle from the livestock markets, most were bullocks but 20 small farmers and 5 medium farmers used female animals for ploughing. Among the indigenous breeds, Kangeyam (33 %) and Hallikar (30 %) breeds were the most popular for work. Most farmers (69 %) provided a mixed type of housing (provision of housing only during the night time and the rainy season) for their draught cattle. The major health problem reported by 63 % of respondents was pyrexia. Almost all farmers sold their animals at the age of 8–10 years. The feeding practices for draught cattle were poor especially with the small farmers. The cattle were fed with mainly paddy straw and rice bran. Oilcakes and cotton seeds were given to the animals which work throughout the year mainly for ploughing and carting. The draught cattle were first shod at around 2.5 years of age. The majority of the farmers (71 %) used the traditional animal-drawn implements made by local artisans, and the farmers were not aware of the new implements to reduce the drudgery of work cattle, designed by the Agricultural Machinery Research Centre and Agricultural Engineering Departments located in India.  相似文献   

Effect of probiotic supplementation on growth,nitrogen utilisation and serum cholesterol in broilers     

B. Mohan  R. Kadirvel  A. Natarajan  M. Bhaskaran 《British poultry science》1996,37(2):395-401

1. The effect of dietary probiotic supplementation on the growth, nitrogen utilisation and serum cholesterol content of broiler chickens was studied in 2 trials.

2. In experiment 1, the birds receiving the 0, 75, 100, 125 mg probiotic/kg diets had weight gains of 1204.0, 1272.0, 1268.3 and 1210.5 g, respectively at the end of 8 weeks of feeding. The group of birds fed on the 75 mg probiotic supplemented diet retained significantly (P<0.01) more nitrogen than the control birds. Serum cholesterol content was lower in the probiotic‐supplemented birds (93.3 mg/100 ml) compared to the control birds (132.2 mg/100 ml).

3. In the second experiment the probiotic plus antibiotic‐supplemented group of birds had the maximum weight gain (1148.5 g) followed by antibiotic (1141.3 g), probiotic‐supplemented (1128.4 g) and control birds (1045.6 g) after 6 weeks. Nitrogen retention was greatest in the antibiotic—(48.5%) followed by the probiotic—(46.5%), probiotic plus antibiotic‐supplemented groups (46.3%) compared to 40.2% in control birds.

4. The apparent metabolisable energy was greatest in birds receiving the probiotic plus antibiotic‐supplemented diet (12.37 MJ/kg) followed by antibiotic—(12.00 MJ/kg), probiotic‐supplemented birds (11.92 MJ/kg) than in control birds (11.62 MJ/kg). Serum cholesterol was significantly (P<0.01) lower in probiotic‐supplemented birds (86.1 mg/dl) compared to 118.4 mg/dl in control birds.  相似文献   

NSF and Science Education     

Natarajan KV 《Science (New York, N.Y.)》1981,212(4499):1085-1086

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Determination of theanine in commercial tea by liquid chromatography with fluorescence and diode array ultraviolet detection   总被引：1，自引：0，他引：1  

Thippeswamy R  Gouda KG  Rao DH  Martin A  Gowda LR 《Journal of agricultural and food chemistry》2006,54(19):7014-7019

Two liquid chromatographic methods that involve precolumn derivatization with o-phthaladehyde (OPA) and phenylisothiocyanate (PITC) with fluorescence and diode array UV detection for the determination of theanine have been developed. The chromatographic separations were achieved by reverse-phase high-performance liquid chromatography using octadecyl columns and gradient elution. The methods were applied to evaluate the theanine content of commercial tea leaves. The coefficient of variation of the peak area repeatability for within day (n = 8) and between day (n = 8 over 10 days) was lower than 3% for both of the methods. The estimated limit of detection (LOD) and limit of quantitation (LOQ) for the OPA method was 0.12 and 0.35 microg theanine, respectively. The PITC method was 500-fold more sensitive with LOD and LOQ values of 0.25 and 0.75 ng, respectively. The theanine content of the commercial tea samples varied from 2-5 mg/g leaf. The overall % recoveries for these methods ranged from 93-99.3. The sensitivity and simplicity of the method render them suitable for use in quality control laboratories.  相似文献