Esters of 3-monochloropropane-1,2-diol and glycidol: no formation by deep frying during large-scale production of potato crisps

In Germany, the best‐selling fish products are canned and marinated fish products including deep‐fried and pickled herring products. During processing, pre‐salted herring fillets are breaded, deep‐fried, and covered by an aqueous marinade containing vinegar and sodium chloride. For shelf‐life extension, the packaged fish can be pasteurized. Due to the co‐occurrence of sodium chloride and glycerol derivatives such as tri‐ or diacylglycerides, the deep‐frying and pasteurization procedure may lead to the formation of fatty acid esters of 2‐monochloropropane‐1,3‐diol and 3‐monochloropropane‐1,2‐diol (MCPD‐E) and of glycidol (G‐E). Various product as well as process dependent parameters on the formation of MCPD‐E and G‐E in deep‐fried and pickled herring products are studied. The frying‐life of the oil has the strongest effect on the formation of MCPD‐E in herring products. 3‐MCPD‐E contents increases from 341 ± 48 to 1133 ± 194 μg kg−1 lipid in the products after 9 days frying‐life of the oil. Moreover, it is shown that the major proportion of MCPD‐E in these products originates from the deep‐frying oil. The analyses of total polar material and spectrophotometric measurement of the absorption at 420 nm of the deep‐frying oil are identified as suitable screening methods for estimating MCPD‐E contents in deep‐fried and pickled herring products. Practical Applications: Canned and marinated fish products are the best‐selling fish products (28% market share) on the German market. Up to now, no studies regarding the deep‐frying procedure of pickled herring products are published. Deep‐frying has shown to be a process leading to MCPD‐E and G‐E in fish products mainly affected by intake of deep‐frying oil. The knowledge about the effect of process and product based parameters on the formation of MCPD‐E and G‐E in deep‐fried and pickled herring products may be of particular interest for the fish‐processing industry in order to manage that quality issue. Moreover, methods for the assessment of the deep‐frying oil quality such as the analysis of the total polar material (TPM) and the spectrophotometric measurement of the absorption at 420 nm deemed suitable screening methods for estimating the MCPD‐E contents in deep‐fried and pickled herring products. Deep‐frying of pickled herring products leads to the formation of MCPD‐E and G‐E, mainly affected by intake of deep‐frying oil and the frying‐life of the oil. Methods for the assessment of the frying oil quality, such as the analysis of TPM and the spectrophotometric measurement of the absorption, are suitable screening methods for estimating the MCPD‐E contents in deep‐fried fish products.

Section: Resultssupporting

confidence: 54%

Section: Comparison Of Mcpd-e and G-e Contents In Deep-fried Herring supporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Formation of Ester Bound 2‐ and 3‐MCPD and Esterified Glycidol in Deep‐Fried and Pickled Herring Products

Merkle

Ostermeyer

Rohn

et al. 2018

“…The highest concentrations were observed in fried chopped onion and garlic. However, Dingel and Matissek showed that 3‐MCPD esters did not formed during deep frying of potato crisps in large‐scale industrial production using high‐oleic sunflower oil. Similarly, Hammouda et al reported that deep frying using mixtures of olive pomace oil and refined palm oil did not lead to significant effects on the formation of 3‐MCPD esters and glycidyl esters.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Formation of Free and Bound 2‐ and 3‐Monochloropropane‐1,2‐Diols During Deep Frying of Leavened Dough Using Response Surface Methodology

Turan

Solak

Keskin

2019

This study aims to determine the effects of frying temperature, frying time, and salt content of dough on free and/or ester‐bound 2‐ and 3‐monochloropropanediols (MCPD) content of leavened dough and frying oil using response surface methodology. According to the results, the amount of ester‐bound 3‐MCPD in fried dough is 4.83–55.00 μg kg−1 dough and free 3‐MCPD is 2.69–50.97 μg kg−1 in fat‐free dough. All process parameters affect the amount of free 3‐MCPD of fried dough significantly (p < 0.05). Moreover, the salt content of the dough does not significantly (p > 0.05) affect the amount of ester‐bound 3‐MCPD in fried dough. Binary interaction of frying temperature and time is significant (p < 0.05) for free and ester‐bound 3‐MCPD content of dough samples. 3‐D plots show that high frying temperature and extended time during deep‐frying result in high levels of free and ester‐bound 3‐MCPD in leavened doughs. A quadratic model is obtained for ester‐bound 2‐MCPD of the fried doughs and frying oil as a function of frying temperature, frying time, and dough salt content. Optimum frying conditions are also determined to minimize generation of MCPD compounds. Practical Applications: Consumption of MCPDs and their esters, which are process contaminants, might adversely affect human health. Therefore, determination of free and ester‐bound MCPD is important in frying oils and fried foods like fried doughs. This research shows the usability of response surface methodology for the investigation of the generation of free and ester‐bound MCPD compounds in fried doughs and frying oil depends on the process conditions. The effects of repeated frying on the content of these contaminants can be demonstrated by quadratic models. To minimize these contaminants during the repeated deep‐frying of leavened doughs, the process conditions should be controlled. The knowledge obtained may provide information about fried‐food safety in terms of MCPD compounds. Fried doughs are consumed in most parts of the world. Frying of leavened dough may lead to the formation of free and ester‐bound 2‐ or 3‐monochloropropanediols (2‐ or 3‐MCPD). In this study, the effects of frying temperature, frying time, and dough salt content on the content of MCPD compounds in leavened doughs and frying oil are investigated using response surface methodology.

Impact of Added Phytosteryl/Phytostanyl Fatty Acid Esters on Chemical Parameters of Margarines upon Heating and Pan‐Frying

Raczyk

Bonte²,

Matthäus³

et al. 2017

The effect of the thermal treatment on chemical parameters of margarines enriched with phytosteryl fatty acid esters is evaluated. Sterols, fatty acids, polar and volatile compounds, dimers, trimers, tocopherols, 3‐MCPD and glycidyl esters are analyzed applying GPC‐RI, GC‐FID, GC‐MS, and HPLC. Additionally, a Rancimat test is performed to compare the oxidative stability of margarines. This study shows that margarines with and without added phytosteryl esters are both stable at a mild temperature of 60 °C over a period of at least 7 days. On the other side after 15 min of pan‐frying at 180 °C a degradation of unsaturated fatty acids (14–47%), phytosterols (31–49%), and vitamin‐E‐active compounds (71–100%) is found. The supplementation of margarines with phytosteryl fatty acid esters have no effect on their oxidative stability during pan‐frying characterized by Rancimat test and total polar compounds. Volatile, degradation products of fatty acids as well as phytosterols, are found after pan‐frying. The composition of volatiles after pan‐frying significantly differed depends on the presence of additional PSE in margarines. For the first time, it is shown that pan‐frying with margarines over a period of 15 min results in a remarkable formation of 3‐MCPD esters while the increase of glycidyl esters is only very moderate. Practical Application: Based on this study results additional phytosteryl esters do not have antioxidative properties on margarines upon pan‐frying. What is more, they are not stable during pan‐frying at 180 °C. A significant amount of nutritionals as phytosterols, vitamin E active compounds, unsaturated fatty acids are degraded within 15 min and other undesired compounds as dimers, trimers, 3‐MCPD esters are formed. According to the research, heating at a high temperature over longer time should not be applied to this kind of product to avoid oxidation of valuable constituents and formation of degradation products. Volatile compounds which were found are characteristic for fatty acids and phytosterols degradation and can be used as indicators of margarines oxidation. The research presents chemical changes in margarines with and without additional phytosteryl/phytostanyl fatty acid esters. In the graphical abstract compounds which naturally occur in those margarines are presented and compounds which are formed after thermo‐oxidative degradation during pan‐frying.