2024 Volume 30 Issue 3 Pages 377-385
We evaluated the quality of the fermented confectionery kouglof made with different oils and fats as ingredients. We tested ghee and grapeseed oil (GO) for their potential health benefits as substitutes for the butter in kouglof, and we observed that the height and specific loaf volume of the kouglof with GO were higher than the those of the butter or ghee kouglof. Compared to the butter or ghee kouglof, the GO kouglof’s hardness value was lower as shown by textural analysis, its bubble volume ratio was higher by 3D/2D image analysis, and its structure model index value was near-oval. The linoleic acid contents of GO and the kouglof with GO were not decreased by baking. These results demonstrate that the GO kouglof was softer and more elastic compared to the butter or ghee kouglof, and that GO can be used as a substitute for butter in terms of health and palatability.
Kouglof, a traditional fermented confectionery resembling a brioche and containing raisins, originated in the Alsace region of France; it is similar to Italian panettone, which is sold at local markets in Japan. The process of making kouglof is almost the same as that used to make common bread, but kouglof is characterized by high amounts of sugar, butter, egg, and dairy products (Kawakita, 2000; Maubourguet et al., 2000). A high oil and fat content is used to increase the extension ability of the kouglof dough and to produce aromatic flavors. Oils and fats are also involved in the control of bread dough aging. Since kouglof contains a high amount of butter, its consumption can contribute to the risk of vascular diseases. We have been interested in making kouglof with high-quality oils and fats as a substitute for butter. We have investigated the use of ghee (which contains medium-chain fatty acids) and grapeseed oil (GO, which contains unsaturated fatty acids) as butter substitutes. Ghee is the oil/fat product that remains after the removal of water and proteins from clarified butter (Kwak et al., 2013). GO is a vegetable oil extracted from grape seeds and contains a high amount of linoleic acid. GO is often used for cooking because of its mild taste and neutral odor.
In France, kouglof is not made with any oil or fat other than butter, and no information about kouglof made with other high-quality oil/fat is available. Our research has focused on the use of oils and fats with expected health benefits as substitutes for the butter in kouglof. In the present study, we used a wild strain of yeast isolated from apple leaves for kouglof dough fermentation; this yeast was rated highly in sensory testing for breadmaking (Komatsuzaki et al., 2016). Herein, we produced three different types of kouglof by using different oils and fats — butter, ghee, and GO — and we then evaluated the quality of each type of kouglof. We performed component analysis of the kouglofs (including total sugar content and fatty acid composition), physical property tests, and 3D/2D images analysis. The results demonstrated the feasibility of a new fermented confectionery using substitute oils and fats.
Strains and media, oils and fats We used a wild yeast, Saccharomyces cerevisiae strain (10-2), isolated from apple leaves (Komatsuzaki et al., 2016). YM medium (1.0 % glucose, 0.5 % peptone, 0.3 % yeast extract, 0.3 % malt extract, pH 6.8) was used for yeast culture. Butter (Yotsuba Milk Products, Hokkaido, Japan), ghee (Flatcraft, Tokyo, Japan) and grapeseed oil (GO) (Ajinomoto, Tokyo, Japan) were purchased at a local market in Tokyo.
Preparation of the yeast The strain 10-2 yeast was inoculated on YM agar medium and incubated at 30 °C for 48 h. The yeast colonies were transferred into a 100 mL Erlenmeyer flask containing YM medium and incubated at 30 °C for 24 h with 150 rpm shaking. Then, 1 mL of the pre-culture solution was transferred into a 500 mL Erlenmeyer flask containing YM medium and incubated at 30 °C for 48 h with 150 rpm shaking. The cultures were centrifuged at 1 400×g for 10 min, and the precipitate was removed. Each collected precipitate was suspended in sterilized water and then centrifuged at 1 400×g for 10 min; the supernatants were removed and the yeast was collected.
Kouglof preparation The kouglof ingredients are listed in Table 1. The following ingredients were used (Calvel, 2001; Kawakita, 2000): flour made in France (Merville semi-strong flour 100 %, protein content 10.0 ± 1.0 %, ash 0.6 ± 0.1 %), oils and fats, eggs, milk (milk fat <3.5 %, Meiji, Tokyo, Japan), dried raisins from Sultana in France, and salt. Pre-fermentation was performed: the collected yeast was mixed with 5 g of granulated sugar and 40 g of milk at 35 °C, and then incubated in a fermenter (model MBCH-32, Maruzen, Tokyo) at 30 °C with 75 % humidity for 10 min.
| Ingredients | Ratio*, % | Amount used, g |
|---|---|---|
| Flour | 100 | 250 |
| Oil and fat** | 38 | 95 |
| Granulated sugar | 18 | 45 |
| Egg | 32 | 80 |
| Milk | 36 | 90 |
| Raisins | 32 | 80 |
| Salt | 2 | 5 |
| Yeast*** (10-2) | 6 | 15 |
Figure 1 illustrates the straight method used to make the kouglofs. The work process of the straight method is short, and the method provides good flavor (Akaishi et al., 2011). The pre-fermentation liquid, whole eggs, and milk were put in the bowl of a tabletop mixer (KitchenAid multi-functional stand mixer, model KSM5, FMI, Tokyo) and mixed well with a whisk. The flour, granulated sugar, wild strain 10-2 yeast, and salt were then added, and the dough was kneaded at medium speed (160 rpm) for 3 min. The oil/fat was mixed into the dough, which was then kneaded at medium speed (160 rpm), and the dough’s softness was checked by the finger test (the condition of fermentation is checked by poking the dough with a finger) and kneaded at medium speed until the dough and oil/fat were well mixed.
Method of kouglof fabrication.
*Yeast: the wild S.cerevisiae strain 10-2.
**Check the condition of femmentation by pushing the dough with a finger.
The mixture was then kneaded at high speed (200 rpm) for 20 min. The differences in the melting points of the butter, ghee, and GO as well as the frictional heat of mixing were considered, and the dough was thus mixed to avoid temperatures >28 °C. When the dough temperature was >28 °C, the dough was placed in a refrigerator and quenched for 5 min. Raisins that had been softened in boiling water and drained were mixed with the dough and kneaded at a low speed (120 rpm) for 3 min. The dough was laid on a stainless steel table and re-rolled, placed in a 24 cm diameter bowl, covered with plastic wrap, and fermented for 60–85 min in a fermenter at 30–32 °C and 75–78 % humidity.
After the finger test, the dough was folded three times for degassing, then re-rolled and molded. The dough was bound up, and a hole was made in the center of the dough with a finger; the dough was then placed in a pottery kouglof mold coated with unsalted butter. The final fermentation was carried out for 80–110 min in the fermenter at 30–32 °C and 75–78 % humidity. In order to match the fermentation conditions for the butter, ghee, and GO, the final fermentation was continued until the dough reached the top inside diameter of the kouglof mold. The pottery kouglof mold with the final fermented dough was baked in an electric oven (model MNHCH-32, Eiwa Seisakusho, Osaka, Japan) with an upper heater at 180 °C and lower heater at 230 °C for 45 min.
Quality evaluation of the kouglofs After baking, the kouglof was cooled at room temperature for 60 min, and then the weight and specific volume were measured. The specific loaf volume of each kouglof was measured by the rapeseed substitution method (Yamauchi et al., 2014). The height of the kouglof was measured by cutting it into two pieces evenly from the upper part of the center. The moisture content of the kouglof was measured using crumbs by the normal pressure-drying method at 135 °C for 60 min. The total sugar content of the kouglof was measured by the phenol-sulfuric method (Manabe, 2003). Arithmetic means from three repetitions were calculated for each type of kouglof, and the average value and standard deviation (SD) were calculated.
Color analysis The crumb and crust colors of each kouglof were evaluated using a colorimeter (model ZE6000, Nippon Denshoku Industries, Tokyo), based on the CIE L*a*b* system. The following parameters were determined: lightness (L*), redness+/greenness (a*), and yellowness+/blueness (b*). The crumb color was measured at the middle point of the center of a 2 cm thick slice. Arithmetic means from five repetitions were calculated for each type of kouglof, and the average value ± SD were calculated.
Texture test The hardness and cohesiveness of each kouglof were measured using the method described by Higuchi et al. (2013). The hard upper and lower ends and the sides of the cooled kouglof were discarded, and the kouglof was then cut with a bread knife at surfaces to 3 cm × 3 cm × 1.5 cm thickness. Crumb samples were ruptured at a speed of 1.0 mm/s up to 80 % strain rate using the No. 6 cylindrical plunger (diameter 8 mm) of a creep meter (RE2-33005B, Yamaden, Tokyo). Arithmetic means from eight repetitions were calculated for each type of kouglof, and the average value ± SD were calculated.
Bubble diameter distribution analysis An approx. 15 mm3 square cube sample (avoiding raisins) was cut out from the center of the kouglof and measured with a cabinet micro-CT scanner (µCT50 scanner, Scanco Medical, Brüttisellen, Switzerland) for bubble distribution analysis of the dough. The measurement conditions were X-ray output: 20–100 kV, maximum analysis range: 50 mm, maximum analysis height: 120 mm, and maximum resolution: 0.5 µm. Two dimensional (2D) slice images, grayscale three dimensional (3D) images, bubble distribution 3D images, and thickness distribution of the 3D dough images were observed. We performed a comprehensive comparison of the bubble volume ratio, structure model index (SMI) value, and number of bubbles among the three kouglof types. The SMI values range from 1 to 5 in five levels; 1 indicates a plate structure, 3 indicates a rod structure, and 5 indicates a sphere structure.
Fatty acid composition of the kouglof, oil, and fats Lipids of powdered samples were extracted by the Folch method (Folch et al., 1957). The fatty acid compositions of the butter, ghee, GO, and kouglof extracts were methylated by the procedure described by Morrison et al. (1964). First, 1.0 mL of 0.5 mol NaOH dissolved in methanol was added to 0.1 mL of sample, and the solution was subjected to vortex mixing and then boiled in a water bath at 100 °C for 10 min. Next, 1.0 mL of boron trifluoride methanol complex solution in methanol was added to the mixture, followed by vortex mixing and incubation in a water bath at 100 °C for 7 min. After cooling, n-hexane (1.5 mL) was added to the mixture and shaken well. The saturated NaCl solution (2.5 mL) was added to the mixture during vortex mixing, followed by centrifugation at 1 400×g at 4 °C for 10 min. The n-hexane phase containing the fatty acid methyl esters (FAMEs) was extracted.
The FAMEs were analyzed by a Hitachi G-3500 gas chromatograph (GC) fitted with a split injector (250 °C) and a flame ionization detector (260 °C) coupled with a chromatointegrator (Hitachi D-2500). We used a TC-70 (70 % cyanopropyl-silphenylene siloxane) column (0.25 mm ID × 60 m length, 0.2 µm film thickness; GL Sciences, Tokyo), with a helium (He) carrier gas flow rate of 1 mL/min. The column was kept at 190 °C for 15 min, heated from 190 to 200 °C at a heating rate of 5 °C/min, kept at 200 °C for 10 min, heated from 200 to 210 °C at a heating rate of 5 °C/min, and kept at 210 °C for 4 min. Each FAME peak was identified with a standard FAME (Funakoshi, Tokyo). Fatty acid composition was expressed as the weight percentage of each fatty acid to total fatty acids.
Statistical analysis The data of weight, height, specific loaf volume, moisture content, total sugar content, color analysis, and texture tests of the kouglofs were performed in triplicate or more, and each value was expressed as the mean ± SD. The results were evaluated by ANOVA. The means were compared by Tukey’s multiple range test with statistical significance set at p < 0.05. The calculations were performed using IBM SPSS Statistics 28.
Characteristics of the kouglofs Table 2 summarizes the characteristics of the kouglofs made with different oil and fat ingredients. There were no significant differences in the weight, moisture content, or total sugar content of the three types of kouglof. The height and specific loaf volume of the kouglof made with GO were significantly higher than those of the kouglofs made with butter or ghee (p <0.05). Figure 2 shows the appearance of the three types of kouglof. The crusts of each type of kouglof showed almost the same thickness. The ‘oven spring’, which is an indicator of expansion, is presented in Fig. 2 and is represented by the distance from the top of the center of the kouglof to the bottom of the center. The oven spring values demonstrated that the kouglof made with GO showed good expansion.
| Butter | Ghee | GO | |
|---|---|---|---|
| Weight, g | 601.0 ± 1.2 | 592.0 ± 5.0 | 596.0 ± 3.2 |
| Height, cm* | 11.7 ± 0.6b | 10.7 ± 0.5b | 12.9 ± 0.7a |
| SLV, cm3/g | 3.17 ± 0.4b | 3.15 ± 0.3b | 4.07 ± 0.2a |
| Moisture content, % | 28.8 ± 1.5 | 26.5 ± 0.9 | 27.3 ± 0.6 |
| Total sugar content, % | 259.0 ± 32.0 | 285.3 ± 3.5 | 289.2 ± 5.6 |
The data are mean ± SD (n = 3). a, b; The values within a column with different superscript letters differ significantly (p < 0.05).
GO: grapeseed oil.
SLV: specific loaf volume.
The appearace of the three types of kouglof.
Height 10 cm is indicated by red arrows.
Oven spring is indicated by blue arrows.
Rows 1, 2, 3: Photographs that were compared with each other three times.
GO: grapeseed oil.
Table 3 lists the results of the crust and crumb color tone of the three kouglof types. There were no significant differences in the crumb color tone of the three kouglofs, but the L*value (34.0 ± 0.98) and b* value (20.7 ± 1.55) of the ghee kouglof crust were lower than those of the crusts of the butter or GO kouglofs.
| Crust | L* | a* | b* |
|---|---|---|---|
| Butter | 38.1 ± 1.44a | 14.7 ± 0.60 | 24.3 ± 1.10a |
| Ghee | 34.0 ± 0.98b | 14.4 ± 1.39 | 20.7 ± 1.55b |
| GO | 39.0 ± 0.86a | 14.9 ± 1.00 | 25.1 ± 0.64a |
| Crumb | L* | a* | b* |
|---|---|---|---|
| Butter | 62.0 ± 0.90 | −2.10 ± 0.54 | 21.3 ± 3.21 |
| Ghee | 61.6 ± 2.33 | 0.99 ± 1.65 | 20.9 ± 2.03 |
| GO | 60.6 ± 0.82 | 1.25 ± 0.49 | 21.8 ± 2.86 |
L*: Brightness, a*: Redness, b*: Yellowness.
The data are mean ± SD (n = 3). a, b; The values within a column with different superscript letters differ significantly (p < 0.05).
GO: grapeseed oil.
Physical properties of the kouglofs Figure 3 illustrates the results of the texture tests of the kouglofs made with the different types of oil and fat. Cohesiveness did not differ significantly among the kouglofs. Although no significant difference in hardness was identified between kouglof made with butter and that made with GO, the hardness value of the GO kouglof was lower than those of the ghee or butter kouglofs (p < 0.05). Figure 4 provides 3D/2D images of the three types of kouglof, and Table 4 summarizes the results of the bubble evaluation of the kouglofs by 3D/2D image analysis, which revealed that the ghee kouglof had the lowest bubble volume (60.8 %), while the volume of the GO kouglof was the highest (70.1 %) of the three. The SMI values of the kouglofs made with butter or ghee indicated nearly spherical bubbles, whereas that of the GO kouglof indicated a nearly oval structure.
Texture tests of kougolf with the three types of oil and fat. The data are mean ± SD (n = 3). a, b; The values within a column with different superscript letters differ significantly (p < 0.05).
GO: grapeseed oil.
3D/2D images of the three types of kouglof. Bubbles are indicated by white arrows.
GO: grapeseed oil.
| Butter | Ghee | GO | |
|---|---|---|---|
| Bubble volume ratio | 67.1 % | 60.8 % | 70.1 % |
| SMI | 4.6 | 4.6 | 3.7 |
| No. of bubbles / 15mm3 | 2733 | 1560 | 571 |
GO: grapeseed oil.
SMI: structure model index. 1 (plate), 3 (rod), 5 (sphere).
Fatty acid composition of the oil, fats, and kouglofs Table 5 explains the fatty acid composition of the butter, ghee, and GO. No differences in total monounsaturated fatty acids were detected among the three types of oil and fat, which ranged from 23.8 to 24.5 %. The fatty acid composition of the three types of kouglof is presented in Table 6. The fatty acid composition of the kouglof made with butter included 66.0 % saturated fatty acids; that with ghee showed 66.9 % saturated fatty acids, and that with GO contained 17.2 % saturated fatty acids. Palmitic acid (16:0) was the most abundant in butter and ghee, and oleic acid (18:1, n-9) was the most abundant monounsaturated fatty acid. The kouglofs made with butter or ghee were low in polyunsaturated fatty acids. These results for the kouglofs were the same as those for the fatty acid composition of the oil and fats. The fatty acid composition of the butter kouglof was 6.2 % linoleic acid (18:2, n-6) and 1.2 % linolenic acid (18:3, n-3), whereas that of the ghee kouglof was 4.8 % linoleic acid (18:2, n-6) and 1.2 % linolenic acid (18:3, n-3). The fatty acid composition of the GO kouglof was approx. 60 % linoleic acid (18:2, n-6), which is similar to the fatty acid composition of GO.
| Butter | Ghee | GO | |
|---|---|---|---|
| Saturated | 72.4 | 73.0 | 13.2 |
| Monounsaturated | 23.8 | 24.4 | 24.5 |
| Polyunsaturated | 2.3 | 2.1 | 61.6 |
| Not determined | 1.5 | 0.5 | 0.7 |
| 100.0 | 100.0 | 100.0 |
GO: grapeseed oil.
| Fatty acids | Butter | Ghee | GO |
|---|---|---|---|
| Saturated | |||
| 8:0 | 6.5 | 6.6 | 0.2 |
| 10:0 | 3.1 | 2.9 | 0.1 |
| 12:0 | 3.3 | 3.1 | 0.1 |
| 14:0 | 11.4 | 10.9 | 0.5 |
| 15:0 | 1.0 | 1.2 | 0.1 |
| 16:0 | 31.2 | 33.0 | 11.2 |
| 18:0 | 9.5 | 9.2 | 5.0 |
| Total | 66.0 | 66.9 | 17.2 |
| Monounsaturated | |||
| 14:1 | 1.0 | 1.0 | 0.0 |
| 16:1 | 1.7 | 2.0 | 0.5 |
| 18:1 (n-9) | 23.2 | 23.4 | 25.1 |
| 20:1 | 0.6 | 0.5 | 0.2 |
| Total | 26.5 | 26.9 | 25.8 |
| Polyunsaturated | |||
| 18:2 (n-6) | 6.2 | 4.8 | 56.2 |
| 18:3 (n-3) | 1.2 | 1.2 | 0.6 |
| Total | 7.4 | 6.0 | 56.8 |
| Not determined | 0.1 | 0.2 | 0.2 |
| 100.0 | 100.0 | 100.0 |
GO: grapeseed oil.
We investigated the possibility of making a healthier, high-quality kouglof with oil and fat substitutes for butter, i.e., ghee and GO. We determined the height and specific loaf volume of the kouglof made with GO, and we observed that the GO kouglof expanded well. It was reported that bread with a large specific volume has a softer texture (Sagara, 2009), and it appears that the larger the specific loaf volume of bread, the softer the texture is. Our present results showed that the GO kouglof was characterized by a soft dough, and the oven spring (an indicator of good expansion) was also suitable. These results indicated that kouglof made with GO has high swelling ability.
It was reported that adding butter to bread dough resulted in increased extension of the dough, increased gas retention in the dough, and expanded bread volume (Taketani, 2010). Fats with plasticity were spread in a thin film on the interface of gluten and starch in dough, and the specific loaf volume became higher and the dough extensibility increased (Edo et al., 1991; Fukudome et al., 2014). On the other hand, dough containing liquid oil tends to become loose, and it is difficult to maintain swelling conditions because the liquid oil disperses in the dough as oil drops (Ushijima, 1970). However, in the present study, the GO kouglof had greater height and specific loaf volume values compared to the kouglofs made with butter or ghee. The increased dough volume was attributed to the presence of egg as one of the ingredients of the GO kouglof, and it functioned as an emulsifier. The emulsification of oil in the dough may increase the specific loaf volume. Additional research is required to determine the precise distribution and structure of oil drops in detail by scanning electron microscopy.
The second aspect of kouglof quality examined in this study is color. The color of the kouglof crust made with ghee was darker than that of the kouglofs made with butter or GO. Ghee is an oil/fat that is prepared by heat clarification of butter or cream (Andrewes, 2012; Mohammed, 1998). The browning color of ghee is due to the Maillard reaction, which is a result of the heating process (Andrewes, 2012). We thought that the kouglof made with ghee would reflect the color of the heated ghee. The results showed that the color of the ghee kouglof was darker than the other two types of kouglof. It is possible that the crust color of the ghee kouglof in the present study was dark due to heating twice at a high temperature. We speculate that this color phenomenon is related to the smoke points of oil and fat. The smoke point is the temperature at which smoke begins to appear when oil or fat is heated (Yamazaki et al., 2021). When oil/fat is heated for a long time, its coloration darkens, the smoke point of the oil/fat decreases, and the acid value of the oil/fat increases (Yamazaki et al., 2021). The smoke point is an indicator of the level of deterioration of oil and fat (Yamazaki et al., 2021). A decrease in the smoke point indicates the oxidation of oil and fat.
Ghee is suitable for high-temperature cooking because its smoke point is 250 °C (Bari et al., 2019). Oil and fat have the characteristic of decreasing smoke point. When oil and fat are heated many times at a high temperature, the color becomes darker due to oxidation (Yamazaki et al., 2021). It was reported that volatile substances such as aldehydes, ketones, and alcohols are produced by long durations of straight heating, and as a result, the smoke point of oil and fat decreases (Yamazaki et al., 2021; Winkler-Moser et al., 2015). It is quite likely that the kouglof made with ghee in the present study more easily produced volatile substances compared to the kouglofs made with butter or GO. We noticed a waxy odor from the ghee kouglof in this study. We suspect that this may have affected the coloration of the kouglof dough, as volatile substances accelerated the evaporation of water from the dough. This phenomenon would also be related to color, since the water would evaporate easily.
The crust color of the GO kouglof was the lightest among the three types of kouglof. GO is a refined vegetable oil; thus, its smoke point is high, approx. 190–230 °C (Bail et al., 2008). We thus speculate that the GO kouglofs crust color was lighter because GO is a highly refined oil with a high smoke point, and an increase in its volatile substances is difficult to achieve.
The third quality point involves the physical properties and the results of the 3D/2D image analysis. The texture test results indicated that the kouglof made with GO was softer than the traditional kouglof made with butter. This result was in good agreement with the specific loaf volume. We evaluated the shape, the number of bubbles, and the distribution of bubbles in the three types of kouglof by conducting 3D/2D image analysis. It was reported that dough elasticity is weak when the shape of the bubbles is spherical, but strong when the bubbles are oval. Inoue (2016) described the effect of bubble shape on oven spring. In the present study, SMI results showed that the GO kouglof had oval bubbles, and as a result, the dough was more elastic than that of the kouglofs made with butter or ghee. Moreover, the GO kouglof had a larger percentage of bubbles per volume than the other two types of kouglof, although they contained lower numbers of bubbles. Therefore, the GO kouglof expanded well, and the findings described above support the dough softness results. These results are in good agreement with the hardness results and Fig. 4. It is reported that good bread is characterized by large bubbles, a thin bubble film, and a soft texture (Ishibashi et al., 2022). Taken together, our findings demonstrated that GO contributes to the softness of the kouglof dough. The kouglof made with GO had a soft and elastic texture as shown by the physical properties and 3D/2D image analysis.
The fourth quality point is the composition of the oil and fats. The oil and fats contain mono- and diglycerides, which have emulsifying activity and are thought to affect the physical properties of kouglof. However, we did not determine the content of mono- and diglycerides, and further investigation is needed on the effect of mono- and diglycerides on kouglof parameters. The fatty acid composition of oils and fats is an important factor for health. As a vegetable oil, GO is healthier than butter, which prompted our investigation of GO in terms of its potential health benefit (Garavaglia et al., 2016; Shinagawa et al., 2015). The linoleic acid contents of GO and the GO kouglof were almost the same, indicating that there was no change in linoleic acid content of the dough after heating. This could be expected to have health benefits.
Our present findings from four types of evaluation suggest that GO could be used as a substitute for butter. (1) The height and specific loaf volume results showed that the kouglof made with GO had greater swelling ability than the kouglof made with butter or ghee. (2) The use of GO may also have an effect on dough softness, since the crust color of the GO kouglof was the lightest among the three types of kouglof. (3) The texture test results showed that the GO kouglof was softer than the traditional butter kouglof. The GO kouglof had a softer and more elastic dough, as reflected by the SMI value (which indicates bubble shape) and the amount of bubbles per volume according to 3D/2D image analysis. (4) The content of the essential fatty acid linoleic acid in GO and the GO kouglof was maintained during baking, and health benefits could be expected from this characteristic. The use of GO (which is tasteless and odorless) allowed the taste and flavor of the other ingredients in kouglof to be more prominent.
We therefore conclude that kouglof made with GO is superior in terms of health and palatability compared to traditional kouglof made with butter. The results of this study revealed that the use of GO is suitable for fermented confectioneries and can provide a novel fermented confectionery with delicious taste and health benefits. We thus expect that kouglof made with GO could be accepted by people who have high health consciousness. Sensory evaluation of kouglof made with GO is expected in the future. A further direction of our research is the application of GO to the production of other fermented confectioneries and sweet breads.
Conflict of interest The authors have no conflicts of interest to declare.
Grapeseed oil
SMIStructure model index
