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Characterization of Aroma Development in Roasting of Peanut

Asha, Singh (2006) Characterization of Aroma Development in Roasting of Peanut. [Student Project Report]

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Abstract

This Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page.

Item Type: Student Project Report
Additional Information: Roasting temperature and time significantly affect (p<0.05) the sensory color. Temperature (linear) and time and interaction of temperature and time affected the sensory color significantly (p<0.05).The co-efficient of determination value for R2 was 0.986 which is a very high and significant indicating the fitness of the second order polynomical equation for the data points. The response surface was maximum as indicated by the negative signs of the Eigen values. The maximum value for sensory color score of 14 was predicted when the temp and time was 105°C and 1019 sec, respectively.Instrumental color L*value was significantly affected by the roasting temperature and time. The temperature (quadratic) and time (linear) and interaction of temperature and time affected the L* value of instrumental color significantly (p<0.01).The co-efficient of determination value is 0.854, which is a very high and significant indicating the fitness of the second order polynomial equation for the data points. The response surface was a minimax as indicated by the mixed signs of Eigen values, in other words it is saddle point where there is no minimum and no maximum. Color a* value was significantly (p<0.01) affected by the roasting temperature and time. It is clear from the ANOVA that the both the temperature (linear), temperature (quadratic) and interaction of temperature and time affected a* value of instrumental color significantly (p<0.01). The co-efficient of determination value (R2) was 0.854, which is a very high and significant .The response surface was a minimax as indicated by the mixed signs of eigen values, in other words it is saddle point where there is no minimum and no maximum. The maximum value for instrumental color a* score of -1.33 was predicted when the temp and time was 106°C and 208 s, respectively. Color b* value was not significantly affected by the roasting temperature and time. The co-efficient of determination value (R2) was 0.899, which is a very high and significant. The response surface was maximum as indicated by the negative signs of the Eigen values. The maximum value for sensory color score of 26 was predicted when the temp and time was 98°C and 960s, respectively. Texture was significantly affected by the roasting temperature and time that the both the temperature (quadratic) and time (quadratic) affected the texture value significantly (p<0.01) and interaction of temperature and time is not affected the texture. The value for R2 was 0.879, which is a very high and significant indicating the fitness of the second order polynomial equation for the data points. The response surface was maximum as indicated by the negative signs of the Eigen values. The maximum value for texture score of 351 was predicted when the temp and time was 101°C and 1011s, respectively. The maximum force was obtained in optimum roasted samples while over roasted samples had less peak force probably due to moisture loss and the texture becomes brittle. This was supported by the number of peaks also. Raw samples had a value of 171.86N and it is increased to 357 N for optimum roasted samples indicating the rigid nature of the texture due to roasting. The initial peak also followed the same trend observed for peak force. Maximum peak force (N) for raw sample is 202.64 and it increased up to optimum roasted samples(355.74N) and then decreased finally in over roasted sample(187.73).First major break slope (N/S) for raw was 18 increased continuously up to over roasted samples. In optimum roasted sample it is 45.68 and in over roasted it was 51(N/S).First major break peak force(N) It is also increased from raw (31.55 N) to optimum roasted sample (35) and finally decreased in over roasted sample(21).Number of peaks are maximum (17) in over roasted samples and then in optimum roasted samples (13). Average peak force (N) is maximum in optimum roasted sample (357 N) and minimum in raw sample (171.8N). Moisture content was significantly affected by the roasting temperature and time. It is clear from the ANOVA that the both the temperature (linear), time (linear) and interaction of temperature and time affected the moisture significantly (p<0.001) level. The co-efficient of determination value for R2 was 0.984 which is a very high and significant indicating the fitness of the second order polynomial equation for the data points. The response surface was a minimax as indicated by the mixed signs of Eigen values, in other words it is saddle point where there is no minimum and no maximum. Scanning electron microscopy study indicated that surface cracks were not visible raw peanut samples while it is clearly visible in over roasted samples, probably due to the moisture loss and appearance of cracks due to skin shrinkage. From the powdered samples, raw was more intact, while roasted samples had components separated, on the other hand the starch molecules photos taken from the samples indicated that the molecules from raw was more round in shape and not ruptured while it started becoming big as the heat treatment becomes severe. From GC-MS studies, in raw peanut sample more volatiles compounds were present (>33) while, in roasted samples the number of samples were less (<10) for under, opt and over roasted samples. The less number of samples present in roasted samples could be attributed to the thermal treatment and the severity of the thermal treatment. As expected, the low volatile compounds were getting volatile and escape during roasting. The typical roasting peanut aroma may be due the presence of molecules present in and also changes of forming combination for flavour molecules in the head space. Analysis by e-nose indicated in raw sample the X axis value is 90.01 % while the Y-axis explained the 9.95% of the total variation in the data. The samples are located on the positive side of the x axis and there is no significant difference between the duplicates. From sensory data it can be concluded that raw samples were more creamish and shiny than roasted samples. Raw and under roasted samples had raw flavor and aroma, while over-roasted samples had burnt charred flavor and aroma. Color of roasted and over roasted eanuts were varied yellowish to brown. The texture of over roasted peanuts was brittle and very hard than raw and under roasted peanuts so over roasted samples requires more biting force. The mean score for overall quality for raw peanut, under roasted, optimum roasted and over roasted was 7.39,8.00, 11.13 and 5.35 respectively. By following these attributes optimum roasted samples are the best according to panelist.
Uncontrolled Keywords: peanut aroma development roasting peanut characterization aroma
Subjects: 600 Technology > 08 Food technology > 22 Legumes-Pulses > 03 Peanut
600 Technology > 08 Food technology > 15 Flavour/Fragrance/Perfumes > 01 Sensory evaluation
Divisions: Sensory Science
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 12 Apr 2007
Last Modified: 28 Dec 2011 09:26
URI: http://ir.cftri.com/id/eprint/452

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