5 results
Evaluation of volatile compounds in different types of ghee using direct injection with gas chromatography-mass spectrometry
- UDAY R. WADODKAR, JAGJIT S. PUNJRATH, AMRISH C. SHAH
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- Journal:
- Journal of Dairy Research / Volume 69 / Issue 1 / February 2002
- Published online by Cambridge University Press:
- 17 June 2002, pp. 163-171
- Print publication:
- February 2002
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Desi ghee (DG) was prepared from fermented cream followed by heat clarification (desi method) in the laboratory and butter oil (BO) was prepared from fresh butter by melting and centrifugation. Fresh samples of three brands of industrial ghee (IG-1, IG-2, IG-3) were collected from the local market. Volatile compounds of desi and industrial ghee and butter oil were isolated and concentrated using direct injection and cryofocussing techniques; separation and identification was by Gas Chromatography Mass Spectrometry (GCMS). A maximum of 36 compounds were detected in desi ghee whereas compounds detected in three industrial ghee samples varied from 22–29. The lowest number of compounds (16) was detected in butter oil. Of the identified compounds, maltol, 5-hydroxymethyl furfuraldehyde, dihydrodihydroxypyranone, 1,3-butanediol and 1-octanol were identified only in desi ghee volatiles. The concentration of acetic acid was found to be remarkably higher in desi ghee volatiles than in industrial ghee. Also the levels of identified fatty acids, methyl ketones, aldehydes, lactones and alcohols were high in desi ghee volatiles compared with industrial ghee and butter oil. In total, 62 compounds were detected, which included 6 aldehydes, 12 ketones, 8 each of fatty acids, alcohols and lactones, 4 each of esters and hydrocarbons or other compounds, and 12 compounds remained unidentified.
Conditioned feeding responses of sheep towards flavoured foods associated with casein administration: the rôle of long delay learning
- G. Arsenos, J. Hills, I. Kyriazakis
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- Journal:
- Animal Science / Volume 70 / Issue 1 / February 2000
- Published online by Cambridge University Press:
- 18 August 2016, pp. 157-169
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- February 2000
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The objective of two experiments was to investigate whether a delayed type of learning could account for the conditioned feeding responses of sheep towards novel food flavours associated with post-ingestive consequences (PIC) created from the administration at different points in time of a nutritive stimulus (casein). The doses of casein were low (15 g) and high (75 g) for experiments 1 and 2, previously known to result in positive and negative PIC respectively. Each experiment consisted of three conditioning periods, during which sheep were trained to associate one of two novel flavours with either casein or water (placebo) administration. During each conditioning, a novel flavoured food low in protein and relatively high in energy, was offered for 3 h (08:00 to 11:00 h) and was followed by an unflavoured, nutritionally similar food for the rest of the feeding time (11:00 to 17:00 h). Sheep were randomly assigned to one of three treatments that were defined by the time when casein or water doses were administered, in relation to the presence of the flavoured food (A= 08:30 and 10:00, B= 11:30 and 13:00 and С = 14:30 and 16:00 h respectively). At the end of each conditioning period preference tests were performed, where sheep were offered a choice between the two flavoured foods. There was no effect of time of casein administration on the conditioned responses towards flavoured foods in either experiment. In both experiments, the proportion of the flavoured food selected was significantly affected by the interaction between preference tests and casein association. For experiment 1 this was due to an increasing preference for the casein associated food accompanied by a decreasing preference for the water associated flavoured food as a result of repeated conditioning. The degree of such preference was different between flavours used for association with casein or water. For experiment 2 avoidance of the casein and preference for the water associated food were established after the completion of the second and reinforced by the third conditioning period. Flavours used had a lesser effect on the conditioned responses of this experiment. The results support the view that sheep develop conditioned responses towards novel food flavours associated with the administration of a nutritive stimulus, even when the PIC resulting from its administration are significantly disassociated in time from the presence of the flavoured food.
Conditioned feeding responses in sheep to flavoured foods associated with sulphur doses
- J. Hills, I. Kyriazakis, J.V. Nolan, G.N. Hinch, J.J. Lynch
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- Journal:
- Animal Science / Volume 69 / Issue 2 / October 1999
- Published online by Cambridge University Press:
- 18 August 2016, pp. 313-325
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- October 1999
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A study was conducted to determine whether sheep form conditioned flavour aversions (CFAs) or preferences (CFPs) for food flavours associated, respectively, with excessive or appropriate concentrations of sulphur (S) and also whether the rate of formation and strength of CFAs and CFPs are dependent on the animal's initial S status or the level of administration of S. In experiment 1, 48 mature ewes were conditioned to associate a new food containing a novel flavour with an infusion of S delivered intra-ruminally, or the same food containing another novel flavour with an infusion of distilled water. The same flavours were then used in experiment 2. At the end of each conditioning period, the relative preference for the two flavoured foods was determined by measuring the amount of each food ingested during a two-choice, 20-min preference test. Experiment 1 consisted of two phases. In phase 1 each conditioning period lasted for 5 days and was repeated four times, whereas in phase 2 the conditioning period lasted for 8 days and was repeated three times.
In experiment 1 the sheep were initially in an S-adequate state. In experiment 2, the sheep were re-randomized to treatments and started in an S-depleted state. The conditioning periods also lasted for 8 days and were repeated three times. There was no evidence to support the hypothesis that sheep develop CFAs or CFPs to food flavours associated with S doses in phase 1 of experiment 1. In phase 2, however, sheep formed CFAs towards the food with the flavour they had come to associate with administration of high levels of S. Repeated exposure to the flavour associated with high levels of S led to stronger aversions and there was an interaction between the S dose level and conditioning periods, indicating that the rate of development of these CFAs was highest for the highest S dose levels. The differences between results of phase 1 and 2 were probably due to the different numbers of reinforcements and different intervals between specific flavour/dose associations.
In experiment 2 there was no evidence for the development of CFPs or CFAs to food flavours associated with S doses. The apparent indifference of the sheep to S was probably due to their responding more to their previous experience of the food flavours than to their S status. Spearman rank correlations on flavour preferences indicated that conditioned flavour responses formed in experiment 1 persisted in individual sheep when they were allocated at random into their new treatments in experiment 2 and influenced or masked the formation of new associations. This demonstration of ‘carry-over’ effects highlights the importance of considering an animal’s previous experience of flavours and their associations with post-ingestive consequences when coming to conclusions concerning current development of CFAs and CFPs. These results may also have more general implications for feeding studies in animals that are randomized into treatment groups without regard to their previous feeding experiences.
The rate of intake of sweet, salty and bitter concentrates by dairy cows
- P. C. Chiy, C. J. C Phillips
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- Journal:
- Animal Science / Volume 68 / Issue 4 / June 1999
- Published online by Cambridge University Press:
- 18 August 2016, pp. 731-740
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- June 1999
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Changes in the formulation and flavour of concentrate foods may temporarily reduce their acceptability to cattle, leading to reduced intake when they are offered for a limited time during milking. The rate of intake of 12 dairy cows offered 1 kg of salty or bitter concentrates was compared with a sweet concentrate, with or without an artificial sweetener to mask adverse flavours. The cows were offered the test concentrates twice a day in a Latin-square design with seven feeding occasions per period and the apparent and actual (excluding non-feeding time) food intake rates were recorded for all seven feeding occasions. Both apparent and actual intake rates were slower for the bitter compared with the salty and sweet flavoured concentrate.
For the first two feeding occasions the intake rate was recorded separately for the 1st min and the subsequent period until the end of feeding. The intake rate was faster in the 1st min because of more rapid prehension of the food and fewer interruptions to the feeding process. Where no mask was included there was no effect of flavour on the apparent intake rate in the 1st min of the first feeding occasion but in the 1st min of the second feeding occasion the apparent intake rate of the salty concentrate was less than that for the sweet or bitter concentrates. The actual intake rates of the bitter and salty concentrates were less than for the sweet concentrate. The mask increased the apparent intake rate of the bitter and sweet concentrates in the 1st min of both the first and second feeding occasions, by reducing the non-feeding time and it also increased the actual intake rate of salty concentrates.
After the 1st min the apparent intake rate of the salty concentrate was faster than that of the bitter and sweet concentrates, where no mask was included. The mask increased the apparent intake rate of the sweet concentrates at this time but reduced it for salty and bitter concentrates. It therefore reduced the acclimatization to the salty and bitter concentrates and enhanced the attractiveness of the sweet concentrates.
There was a residual effect from the previous period of concentrates which were eaten slowly i.e. salty concentrates, which reduced the 1st min intake of foods that were eaten rapidly, i.e. sweet concentrates, in the subsequent period. This was largely due to increases in the time spent pausing between bouts of food ingestion. After the 1st min the apparent intake rate of cows receiving salty concentrate for a second consecutive period was increased, suggesting acclimatization. The opposite effect was observed for the sweet concentrate, probably because the novelty of the sweetness had diminished, making it relatively less attractive to the cow. This experiment therefore provides evidence that bitter and to some extent salty concentrates are consumed at a slower rate than sweet concentrates, except for the 1st min in which they are offered to cattle and that a reduced concentrate intake rate may persist after the flavour is removed from the food. Cattle did, however, demonstrate an ability to acclimatize to salty concentrate over time.
Effects of monosodium l glutamate on diet palatability and piglet performance during the suckling and weaning periods
- F. Gatel, P. Guion
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- Journal:
- Animal Production / Volume 50 / Issue 2 / April 1990
- Published online by Cambridge University Press:
- 02 September 2010, pp. 365-372
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- April 1990
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The effect of monosodium L glutamate (MSG) on diet palatability and piglet performance during the suckling and weaning periods was studied in the course of five successive experiments involving a total of 230 litters during the suckling period and 120 pens of seven piglets during the post-weaning period. During the suckling period, the addition of 5 g MSG per kg diet led to a significant 0·36 proportional increase of creep food intake from the 18th day post farrowing. However, no increase in weaning weight was observed subsequent to the intake of the diet with added MSG. Moreover, in an experiment where MSG was added with an associated commercial flavour, no flavour enhancing effect of MSG was detectable. Few health problems were encountered at weaning and the number of scouring piglets was not related to one particular diet. During the first 13 days after weaning the addition of MSG to the diet increased daily food intake by proportionately 0·1 (P < 0·01) as well as growth rate by proportionately 0·07 (P < 0·01). Moreover, the addition of MSG to the diet was more effective with piglets of low weaning weight and thus contradicted the classical relationship between post-weaning performance and weaning weight. Finally, in an experiment where weaning occurred at lower ambient temperature, no improvement of post-weaning performance was observed following the addition of MSG.