Bigels containing different wax-based oleogels as laminating fat replacers in croissants

Abstract

In this study, bigels were developed to mimic the characteristics of traditional laminating fats, butter and margarine, in croissants. The bigels consist of 80 % oleogel (canola oil, wax and monoacylglyceride) and 20 % hydrogel (water and xanthan gum). Beeswax (BW), carnauba wax (CBW), candelilla wax (CLW), and rice bran wax (RBW) were evaluated as oleogelators at concentrations between 12 and 20 % w/w in the oleogel. The effects of wax concentration, temperature, and mechanical work (plasticizing) on texture, solid fat content, and microstructure of the bigels were investigated. Bigels' solid fat content and mechanical properties were less temperature sensitive than controls, but mechanical work (plasticizing) had detrimental effects on their texture. Differences in bigel firmness between waxes at the same concentration could be attributed to different wax crystal structures. Plasticized bigels most similar in texture to the controls were those with 18 % BW, 14 % CBW, 14 % CLW, and 20 % RBW. These bigels were tested as laminating fats in croissants at 100 % replacement levels. After lamination, the croissant doughs with bigels exhibited irregular fat layering, resulting in more dense and less airy croissant pore structure. While bigel croissants possessed a comparable volume, they were generally flatter and wider compared to croissants with control fats. In terms of texture, bigel croissants displayed a lower degree of staling, but had overall higher firmness. Furthermore, they had similar springiness and cohesiveness, but increased chewiness. With respect to nutritional value, croissant made with bigels contained significantly less saturated fatty acids.

Keywords: Bigel; Croissants; Laminated pastry; Solid fat replacer; Texture; Waxes.

Graphical abstract

Fig. 1

Top (left) and side view (right) of croissants before baking (bar length: 10 mm).

Fig. 2

Pictures of fat samples for texture analysis before plasticizing (top and side view). Dimensions: 21.5 mm diameter, 15 mm thickness; BW: beeswax, CBW: carnauba wax, CLW: candelilla wax, RBW: rice bran wax, all presented bigels contained 12 % wax in the oleogel.

Fig. 3

Influence of wax concentration, temperature and plasticizing on firmness of different wax bigels. (A,B) beeswax, (C,D) carnauba wax, (E,F) candelilla wax, (G,H) rice bran wax at wax concentrations between 12 and 20 % in the oleogel; left column before plasticizing, right column after plasticizing; black = 10 °C, grey = 15 °C, white = 20 °C. Reference lines indicate mean firmness of margarine at 20 °C, solid line = unplasticized, dashed line = plasticized. Different lower-case letters indicate significant differences within graphs (p < 0.05).

Fig. 4

Solid fat content of control fats and bigels at different wax concentrations between 12 and 20 % in the oleogel. (A) butter and margarine, (B) beeswax, (C) carnauba wax, (D) candelilla wax, (E) rice bran wax.

Fig. 5

Microstructure of selected bigels. (A) 18 % beeswax, (B) 14 % carnauba wax, (C) 14 % candelilla wax, (D) 20 % rice bran wax in the oleogel. Bar length: 100 μm.

Fig. 6

Structure of pastry dough layers (dark: dough, light: fat) and corresponding cross-sections of croissants obtained with control fats margarine (M) and butter (B) as well as selected bigels made with 18 % beeswax (BW18), 14 % carnauba wax (CBW14), 14 % candelilla wax (CLW14) and 20 % rice bran wax (RBW20) in the oleogel. Bar length: 10 mm.