Title : Measuring the trans-fatty acid content of various vegetable frying oils using near infrared spectroscopy
Abstract:
A rapid technique for determining the trans fatty acid content of various vegetable frying oils has been developed for assessing its content in fried foods and monitoring its content in frying oils during processing. Eleven types of edible vegetable oils purchased from a supermarket in Japan were used as the raw oils for potato frying. Frozen packaged par-fried French fries were purchased from a local supermarket and used for deep-frying in a restaurantgrade stainless steel electric fryer. The oils were heated at 180 °C for 6 h daily for 6 days, with a total of 10 batches of frozen French fries being fried for 3 min on each frying day. As this way, frying oil samples with different trans fatty acid contents were collected from various vegetable oils used for actually deep-fat frying French fries. NIR spectra in the wavelength range from 400 to 2500 nm were recorded from oil samples in disposable 5-mL test tubes. Partial least square (PLS) regression with full cross validation was used to correlate the trans fatty acid content of frying oils with the near infrared spectra. The partial least squares calibration models had a coefficient of determination (R2) of 0.90, a standard error of prediction of 0.24%, and a ratio of standard error of performance to standard deviation of 2.6 for the independent validation of the trans fatty acid content, in various vegetable frying oil samples. NIR spectroscopy offers a fast and simple method to determine the trans fatty acid contents of various vegetable frying oils.
