Factors Affecting Thermally Induced Furan Formation

Abstract

Furan, a potential carcinogen, can be induced by heat from sugars, ascorbic acid, and fatty acids. The objective of this research was to investigate the effect of pH, phosphate, temperature, and heating time on furan formation. Heat-induced furan formation from free sugars, ascorbic acid, and linoleic acid was profoundly affected by pH and the presence of phosphate. In general, the presence of phosphate increased furan formation in solutions of sugars and ascorbic acid. In a linoleic acid emulsion, phosphate increased the formation of furan at pH 6 but not at pH 3. When an ascorbic acid solution was heated, higher amounts of furan were produced at pH 3 than at pH 6 regardless of phosphate's presence. However, in linoleic acid emulsion, more furan was produced at pH 6 than at pH 3. The highest amount of furan was formed from the linoleic acid emulsion at pH 6. In fresh apple cider, a product with free sugars as the major components (besides water) and little fatty acids, ascorbic acid, or phosphate, small or very low amounts of furan was formed by heating at 90-120 degrees C for up to 10 min. The results indicated that free sugars may not lead to significant amounts of furan formation under conditions for pasteurization and sterilization. Importantly, this is the first report demonstrating that phosphate (in addition to pH) plays a significant role in thermally induced furan formation.

Analysis of furan in heat-processed foods consumed in Korea using solid phase microextraction–gas chromatography/mass spectrometry (SPME–GC/MS)

“…Baby foods were usually heated at high temperatures to secure the microbiological safety of the product. This may have contributed to the increased furan level (Fan et al, 2008). In the present study (102.48 ng/g) as well as that conducted by the US FDA (58-108 ng/g), the furan level of baby food products containing sweet potato was higher than that of other baby food products.…”

“…Moreover, the level of furan was shown to have increased to 370 ng/g after heating of soy (Maga, 1979). For meat and meat products, more furan is formed from linoleic acid at neutral pH because fatty acids are considered to be major furan precursors (Fan, Huang, & Sokorai, 2008). All canned and jarred juice products contained furan between 1.65 and 9.19 ng/g.…”

“…US FDA analysis showed that furan was present in thermally processed juices with levels ranging from non-detectable to 10.2 ng/ g, except for prune juice (23.5-30.5 ng/g; FDA, 2004a). Vitamin C or ascorbic acid is a precursor of furan formation and was often used in fortified juices prior to thermal processing, resulting in increased furan formation (Fan et al, 2008). All jarred baby foods showed a furan content of between 3.39 and 102.48 ng/g.…”

Furan content in Spanish baby foods and its relation with potential precursors

“…Moreover, commercial baby foods may comprise an important part of the diet for many infants. Baby foods are often fortified with vitamin C prior to thermal processing, which would increase furan formation (Fan, Huang, & Sokorai, 2008). Furthermore, food intended for consumption by babies may have been heated at high temperatures to ensure that the product is microbiologically safe, which again increases furan formation.…”

Effect of oxygen availability and pH on the furan concentration formed during thermal preservation of plant-based foods

“…Again, most of the studies are performed with model systems, using phosphate solutions 89 as a buffer for tempering the pH shift during the thermal treatment. However, phosphate ions have 90 recently been shown to enhance furan formation themselves (Fan et al 2008;Huang et al 2011). In real 91 food systems, the complexity is further increased, since the pH can have an indirect effect on the furan 92 formation through interactions with proteins, metal ions or even the structure of the matrix.…”