Promising research is underway that could lead to more accurate ways to measure rancidity than the current practice of measuring peroxide values (PV) and free fatty acid levels (FFA). This research was presented at The Almond Conference last December by Alyson Mitchell, PhD, Food Science and Technology Department, UC Davis.
Rancidity is one of the biggest challenges to providing consumers with the highest quality California Almonds, which occurs when fats and oils break down under certain conditions, giving off an unpalatable odor and flavor.
Dr. Mitchell’s research project had two objectives: to monitor common markers of lipid oxidation and volatile aroma profiles in light and dark roasted almonds undergoing accelerated shelf-life conditions that promote rancidity development over 12 months, and to measure the consumer hedonic response (degree of liking) of light and dark roast almonds to determine how consumer liking correlates with the chemical measures as rancidity developed during accelerated shelf-life storage.
Dr. Mitchell noted that in her research, all chemical measures of rancidity behaved significantly different between light roasted and dark roasted almonds. She noted that at two months, significant decreases were observed in compounds related to roasted flavor (pyrazines), indicating that flavor fade occurs rapidly.
In conclusion, she found that headspace volatiles correlate better with consumer liking than traditional methodologies that look at peroxide values and free fatty acid levels.
