Personal response systems, such as clickers, have been widely used to improve the effectiveness of teaching in various classroom settings. Although hand-held clicker response systems have been the subject of multiple prior studies, few studies have focused on the use of cell phone-based personal response system (CPPRS) specifically. This study explores students' academic performance and their perceptions of learning through the use of a CPPRS (TopHat) in an undergraduate Food Science class. In this study, students did not use the CPPRS during the first half of the semester-long course, but did during the second half. When CPPRS was used, students responded to 2 multiple-choice questions at 3 points during the class, (a) at the beginning of class, (b) in the middle of the class, and (c) at the end of the class. Student performance was measured by correctness rates on eight 10-item multiple choice quizzes, 4 quizzes each covering the class content that was delivered with compared with without CPPRS. A survey was conducted at the end of the semester asking (n = 28) students' perceptions of CPPRS. The average correctness rate for quizzes covering content delivered with CPPRS (85% ± 9%) was significantly higher than for content delivered without CPPRS (82% ± 10%) (P = 0.016). In addition, students perceived that CPPRS was easy to use (5.04 ± 0.58 on a 1 to 6 scale with 1 being strongly disagree and 6 being strongly agree) and positively impacted their learning (4.52 ± 0.99 using the same scale). When used correctly, CPPRS can facilitate student learning in lectures.
Polyphenols in cocoa beans contribute from 12 to 18% dry weight of the whole bean. The major constituent polyphenols in cocoa are catechins (37%), procyanidins (58%) and anthocyanins (4%). Despite the high content of polyphenols in cocoa, cocoa processing including fermentation significantly affects the composition and concentration of polyphenols. Study of cocoa fermentation at the laboratory scale is challenging since industrial cocoa fermentation requires at least 25 kg of fresh wet beans to achieve the proper conditions for fermentation. In this study, dried unfermented cocoa bean and a simulated pulp were used as substrate for laboratory scale fermentation. Microbial and chemical characteristics were monitored over the course of fermentation. Commercially available dried unfermented cocoa bean was first rehydrated with water and then mixed with simulated pulp media developed to ensure the growth of yeast, lactic acid bacteria and acetic acid bacteria, the essential microorganisms for cocoa fermentation. A temperature profile similar to on‐farm cocoa fermentation was acheived using a laboratory incubator. Aeration by shaking the fermentation box at 150 rpm promoted growth of acetic acid bacteria. As a result, internal pH of the cocoa bean decreased from pH 5.73 to pH 4.8 over 7 days of fermentation. By using selective and differential media, yeast growth reached 5.28 × 108 CFU/ml at day 4 and anaerobic bacteria was detected from day 1 and reached the highest concentration of 3.16 × 109 CFU/ml at day 4. Aerobic bacteria was also detected from day 1 and increased gradually to reach a maximum of 2.29 × 109 CFU/ml at day 4. Total concentration of procyanidin (mean ± STDEV) in fermented cocoa bean was analyzed using 4‐Dimethylaminocinnemaldehyde (DMAC) method. Total procyanidin decreased by 64% from day 0 to day 7 (day 0: 0.19 ± 0.01 g procyanidin B2 equivalents/g cocoa extract, day 7: 0.07 ± 0.01 g procyanidin B2 equivalents/g cocoa extract). Folin‐Ciocalteu colorimetric method was performed to determine the total polyphenol content (mean ± STDEV) during fermentation and a 33% decrease was observed from day 0 to day 7 (day 0: 3.63 ± 0.2 g gallic acid equivalents/g cocoa extract, day 7: 2.45 ± 0.2 g gallic acid equivalents/g cocoa extract). The cocoa fermentation model developed in this study will be further employed to evaluate the effect of fermentation conditions on concentration and composition of bioactive compounds and bioactivity thereof in cocoa.Support or Funding InformationVirginia Agricultural Experiment Station salary and startup support for A. Stewart
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