Palm olein quality parameter changes during industrial production of potato chips

Abstract

New legislation introduced in South Africa for the quality of used frying oils has resulted in the need to identify quicker, more suitable methods that correlate well with results from two official methods, namely, total polymerized glycerides and total polar components. Oil and product samples were taken at regular intervals during a commercial frying process in palm olein. Oil samples were analyzed for a number of different quality parameters viz. tocopherol content, dielectric constant, total polymerized glycerides, total polar components, tertiary butylhydroquinone (TBHQ) content, anisidine value, Rancimat induction period, and free fatty acid content, and the results statistically compared to results from official methods. Oil was expressed from product stored under accelerated conditions and analyzed for the same quality parameters. Fried product was also subjected to sensory evaluation to measure the degree of oil deterioration and sensory preference. The frying trial was successfully executed with refined, bleached, and deodorized palm olein and the frying oil used to a free fatty acid (FFA) content of 0.41%. Oil and product sampling were done at different FFA value levels. Frying oil quality was verified at the onset of the trial and at regular intervals. The frying oil total polar component value increased to approximately half of the limit set by the official regulation. This point was reached mainly due to the high starting value of the fresh oil. Frying oil total polymerized glycerides increased from below 1% to 2.1%. This increase is negligible when compared to the general trend for polyunsaturated oils. The alternative laboratory methods used for predicting oil quality can be rated as follows: total tocopherol content > dielectric constant > FFA > TBHQ content > anisidine value > Rancimat induction period. The first three methods correlated well with total polar component levels and it is recommended that the dielectric constant and FFA measurements be applied for monitoring oil condition during frying. It is possible that viscosity changes could be used for the monitoring of polyunsaturated frying oils. Evaluation of oil extracted from product revealed a negligible effect of non-oil components on oil quality parameters. The same was observed when product was stored at -10°C and at 37°C.Paper no. J8849 for JAOCS 76, 731-738 (June 1999).Palm olein is preferred for industrial deep frying of snack products in South Africa either in pure form or combined with other oils. Although several locally produced oils are available, at competitive prices, the main deciding factor in selecting frying oil is based on the shelf life requirements of the fried products. Another deciding factor is the recent introduction of regulations for controlling the quality of used frying oil in South Africa (1). The Department of Health selected two oil quality evaluation parameters, total polymerized glycerides (2) and total polar component contents (3). The two official methods proved to be adequate for regulatory purposes b...

A quality assessment of crude palm oil marketed in Bahia, Brazil

“…The higher amounts of total polar compounds in palm oils are mainly due to a higher level of diacylglycerol contents (4.0-7.5%) compared to other vegetable oils (Berger, 2005;DeMarco et al, 2007). In the studies of fractions of palm olein, Plessis and Meredith (1999), Tarmizi and Ismail (2008) and Ismail (2005) determined polar compound values of 7%, 6.8-7.7% and 6%, respectively. In this study, the polar compound values of the samples produced in Bahia were more than double those reported in the literature.…”

Quality Assessment of Palm Products upon Prolonged Heat Treatment

“…However, most of these studies were performed under batch (discontinuous) frying conditions, which differ from that of continuous frying operation in terms of frying performance and the rate (mechanism) of oil deterioration. Only few papers investigated the performance of palm olein under continuous frying conditions [4][5][6][7][8][9][10] . The role of frying oil is essentially to provide an efficient heat transfer medium.…”

Trans-free fats with the products of the oil palm - a selective review

“…Palm oil or palm olein, with their good resistance to oxidation are today used world wide for industrial frying (Berger 2005) with an estimated use of between 5 and 10 million tonnes/year. Their satisfactory performance in potato crisps (Du Plessis & Meredith 1999;Martin-Porvillo et al 1996;Hammond 2002) and in prefried French fries has been reported (Sebedio et al 1991). In the author's experience palm oil proved satisfactory over a period of years in the frying of doughnuts.…”