The three year accelerated shelf life test on bread pudding was completed in FY2004. The other items are two years old. A summary of the results is as follows:
• Bread Pudding:
o Color: A sharp decline in lightness values was seen between months 7 through 12 indicating the product became darker over this time period.
o Sensory: Sixteen months was the last testing point that the 95oF sample was still acceptable. The 40 degree and 72 degree samples continued to score above the 6.0 standard (out of 9 on a hedonic scale) until the 36-month test conclusion. The decline in overall flavor, level of sweetness, level of vanilla, and overall aftertaste may all be due to Maillard reactions. The Maillard reactions are a series of reactions of free amino groups and reducing sugar resulting in a brown color and toasted flavor. The three most prevalent ingredients; skim milk, sugar and egg, would provide sufficient amounts of free amino groups and reducing sugar to allow for these reactions to occur. It may be hypothesized that these reactions attributed the changes seen in both color and flavor related characteristics.
The Q10 is a measure of how the rate changes for every 10oC change in temperature. The Maillard reaction has different Q10 values depending upon the stage of the reaction. The Q10initial = 2, while flavor intermediate Q10’s range from 2 to 5, and brown color formation Q10’s range from 3 to 8. Using Q10 = 2 (worse case scenario), the 72 degree samples would not reach the same level of degradation until approximately 48 months of storage. The refrigerated, 40 degree F (4.4 degree C) samples would not reach the same level of degradation until approximately 166 months of storage.
• Tuna Noodle Casserole: Only acceptability tests were conducted at 20 months for all temperatures since both 72 degree F and 95 degree F had shown significant differences from control at 16 months. At 20 months, the 95oF samples failed the acceptance sensory test.
At two years of accelerated shelf life testing, the samples stored at 40oF and 72oF are still acceptable. The overall acceptability scores were 7.33 and 6.82 out of a 9-point hedonic scale, for 40oF and 72oF, respectively at 24 months.
• Apricot Cobbler: At 16 months, the difference from control tests showed significant differences at 72 degree F and 95 degree F. When the acceptability tests were run, the 95oF sample failed the sensory test. The 40oF and 72oF samples passed acceptability tests at 20 months and 24 months. The overall acceptability scores were 6.92 and 6.40 out of a 9-point hedonic scale, for 40oF and 72oF, respectively at 24 months.
• Carrot Coins: At 16 months, the difference from control tests showed significant differences. However, when the acceptability tests were run, the all three temperature samples passed. At 20 months, the 95oF sample failed the sensory test. The 40oF and 72oF samples passed acceptability tests at 20 months and 24 months.
The accelerated shelf life test will continue in FY’05 with the 40oF and 72oF samples.