Effects of chalkiness level on sensory aspects of raw and cooked rice samples

Transcription

1 Effects of chalkiness level on sensory aspects of raw and cooked rice samples Red dye Han Seok Seo, Ph.D. Assistant Professor of Sensory Science Department of Food Science Rose wine Red wine White wine I am the best sommelier. Rice Illusion? The nose smells what the eyes see Brown rice? Par boiled rice? Milled rice? (Gottfried & Dolan, 2003) ( rice are more nutritious than white rice/) Grape tomato maturity and ripeness state Physical dimension Grain length Grain width Length width ratio How about rice? Surface color Degree of whiteness Glossiness Chalkiness 4 = Minimum stage for harvest Physical damage Broken kernels Damaged kernels (Source: UC Davis Postharvest Technology) 1

2 RICE Chalky rice? Chalk is the opaque area in the rice grain. Chalk is mainly present at the center of the grain. A RICE B A: Whole chalky kernel B: Cross section of chalky kernel Nighttime high air temperature during specific stages of grain development seem to be the main cause of chalk formation in rice grains. (Lisle et al., 2000; Effects of chalkiness level on sensory aspects Eating & Cooking qualities of cooked rice ( (Cheng et al., 2005) Effects of chalkiness level on sensory aspects Effects of chalkiness level on sensory aspects ( Sensory acceptability of raw, uncooked rice? Sensory acceptability of raw, uncooked rice? It is an undesirable characteristic in all markets except the arborio market; most markets will not accept rice that contains >2% of chalky grain (Lisle et al., 2000) Objectives Objectives s Determine whether chalkiness level affects sensory acceptability of raw (uncooked) rice. Determine whether chalkiness level affects sensory characteristics of cooked rice. CL = Chalkiness level % = Chalky portion (by area using a color sorter) A total of 9 rice samples varyin g in chalkiness level 2

3 s s Chalkiness levels and L* values of the rice samples used in this study. WinSeedle (%) L* value Chalkiness levels of rice samples (by color sorter and mixture) 0% 3% 6% 9% 12% 15% 18% 21% 24% 0.4 (± 0.1) 73.4 (± 0.4) 2.6 (± 1.3) 74.1 (± 0.6) 6.6 (± 0.5) 74.7 (± 0.4) 9.5 (± 0.8) 74.7 (± 0.5) 11.8 (± 3.7) 74.9 (± 0.3) 16.1 (± 1.7) 75.6 (± 0.3) 18.7 (± 2.2) 76.2 (± 0.7) 20.0 (± 5.4) 76.2 (± 0.5) 24.3 (± 1.9) 77.0 (± 0.4) Mean values (±standard deviation) of three replications Experiment 1: Effect of chalkiness level on consumer acceptability of raw rice (by consumer panel). Experiment 2: Effect of chalkiness level on sensory characteristics of cooked rice (by trained panel). Presentations of 9 rice samples US consumers Sensory testing of 9 rice samples Appearance based rice quality as a function of chalkiness level 47 Caucasians (20 M & 27 F) Appearance based rice quality (on a 9 point scale) 1: Extremely bad 9: Extremely good between chalkiness levels Wrapped in a transparent plastic film packet 40 Asians (21 M & 19 F) Overall impression of rice appearance (on a 9 point scale) 1: Dislike extremely 9: Like extremely each chalkiness level Appearance based rice quality as a function of chalkiness level Impression to rice appearance as a function of chalkiness level Caucasian (capital) or Asian (lower case) group. each chalkiness level (P<0.05). between chalkiness levels each chalkiness level 3

4 Impression to rice appearance as a function of chalkiness level With an increase in chalkiness, consumers ratings of grain quality and appearance impression decreased. Caucasian (capital) or Asian (lower case) group. each chalkiness level. (P<0.05). Compared to Caucasians, Asian consumers appear to be more influenced by chalkiness level of rice when they evaluate quality and impression of the raw rice. There was no effect of ethnicity (Caucasians vs. Asians) on rice quality ratings when the consumers evaluated rice samples with 3% or less chalk by area. Q) Why are Asian participants more sensitive to rice appearance compared to Caucasian participants? The most important factor that you consider when purchasing rice grain products. Asians Western rice diet Asian rice diet N = 47 N = 40 Cross regional comparison of rice package designs between the U.S.A. and Asian countries The most important factor that you consider when purchasing rice grain products. Caucasians Caucasians Asians In Asian countries In the U.S.A. N = 47 N = 40 4

5 s Cross cultural difference in visual perception/attention Experiment 1: Effect of chalkiness level on consumer acceptability of raw rice (by consumer panel). Experiment 2: Effect of chalkiness level on sensory characteristics of cooked rice (by trained panel). A photograph taken by N. American participant A photograph taken by East Asian participant (Masuda et al., 2008) Main Questions of Sensory Analysis (Sensory) Analysis: Analytical Approach Discrimination (Difference test) Description Preference / Acceptance ( Analysis) (Affective test) Flavor Profile Quantitative Analysis Time Intensity test Texture Profile Spectrum Analysis Generic Analysis Spider web chart Attribute A Attribute B 5 cooked rice samples sensory analysis Sensory analysis of 5 rice samples Min. intensity Max. intensity Mean value With a 1:2 rice to water ratio 0% CL Spectrum analysis 31 sensory attributes Appearance: 4 Aroma: 5 Flavor: 9 Taste: 4 Texture: 9 Attribute E Sample 1. Sample 2. 6% CL 12% CL 18% CL 15 pt. numerical scale 0: None 15: Extremely strong Min. intensity Max. intensity 24% CL 5

6 Sensory attributes of 5 cooked rice samples as a function of chalkiness level Sensory attributes of cooked rice were not significantly different as a function of chalkiness level (0 to 24%). Explanation 1 Explanation 2 No significant effect of chalkiness level on sensory attributes of cooked rice Chalky kernels have no detrimental effect on sensory attributes of cooked rice. of sensory analysis may vary by the type/procedure of sensory analysis. CL: Chalkiness level (by area) Effects of chalky kernels on sensory quality of cooked rice were not significant unless the % of chalky kernels was 15%. Vitreous kernels : Chalky kernels Sensory attributes of cooked rice were not significantly different as a function of chalkiness level (0 to 24%). Explanation 1 Explanation 2 Chalky kernels have no detrimental effect on sensory attributes of cooked rice. of sensory analysis may vary by the type/procedure of sensory analysis. Kim et al. (2000) Cereal Chem. 77: Conclusion Universal Aromatic Scale (UAS) in Spectrum analysis 3.0 Soda note in saltine cracker (Nabisco) 7.0 Cooked apple note in applesauce (Mott s) 10.0 Grape note in grape juice (Welch s Concord) 14.0 Roastedness in brewed espresso (Medaglia D Oro) It is valuable to develop additional UAS references with low intensities. 4 pt. Conclusion Quality and impression of appearance of uncooked rice is affected by chalkiness level and ethnicity (Caucasians vs. Asians), but once rice is cooked, chalkiness level (ranging from 0 to 24%) of the uncooked rice makes no difference. 6

7 Conclusion NEW Acknowledgements Thank you very much for your supports. University of Arkansas Sensory Science Program Dr. Sungeun Cho Camile Duez Tonya Tokar Trained Panel References Cheng, F.M., Zhong, L.J., Wang, F., Zhang, G.P Differences in cooking and eating properties between chalky and translucent parts in rice grains. Food Chemistry, 90: Gottfried, J.A., Dolan, R.J The nose smells what the eye sees: crossmodal visual facilitation of human olfactory perception. Neuron, 17: Kim, S.S., Lee, S.E., Kim, O.W., Kim, D.C Physicochemical characteristics of chalky kernels and their effects on sensory quality of cooked rice. Cereal Chemistry, 77: Lanning, S.B., Siebenmorgen, T.J., Counce, P.A., Ambardekar, A.A., Mauromoustakos, A Extreme nighttime air temperatures in 2010 impact rice chalkiness and milling quality. Field Crops Research, 124: Lisle, A.J. Martin, M., Fitzgerald, M.A Chalky and translucent rice grains differ in starch composition and structure and cooking properties. Cereal Chemistry, 77: Masuda, T., Gonzalez, R., Kwan, L., Nisbett, R.E. 2008, Culture and aesthetic preference: comparing the attention to context of East Asians and Americans. Personality and Social Psychology Bulletin, 34: