Flour, sugar, commercially available margarine (Simas), eggs, baking powder, and shea butter were purchased from the sango market, Saki, Oyo State, Nigeria. Baking equipment and facilities of the bakery unit of The Oke-Polytechnic Saki, Oyo State, were used for queen’s cake production.

Queen’s Cakes were produced using the method described by Ceserani and Kinton [13Ceserani V, Kinton R. Practial Cookery 10^th ed. 2008; 82.]. The method is as briefly described in Fig. (1). The percentage of complementation levels of shea butter and margarine is presented in Table 1. Shea butter treated with heat (Flashed shea butter) was also used for cake production. Formulations for cake production for various samples are presented in Table 2.

Fig. (1) Cake preparation [13Ceserani V, Kinton R. Practial Cookery 10th ed. 2008; 82.].

Table 1
Shortening mixture of shea butter and margarine.

Weight, height, and volume of the cake samples were the physical parameters measured. The method highlighted by Giami and Barber [14Giami SY, Barber LI. Utilization of protein concentrates from ungerminated and germinated fluted pumpkin (Telfoririaoccidentalis Hook) seeds in cookies formulations. J Sci Food Agric 2004; 84: 1901-7.
[http://dx.doi.org/10.1002/jsfa.1881] ] with slight modification was used to measure the physical characteristics of the cake samples. All physical measurements were taken two hours after baking. The average of five cake samples was recorded for each measurement, and this was done in three replicates for all physical parameters. Digital weighing balance and meter rule were used to measure weight and height, respectively. The queen’s cake volume was estimated using the cone equation presented in equation 1.0.

Where d and b are upper and lower diameters of cake, respectively,

h is the height of the cake and π is 3.142

Queen’s cake samples were analyzed to determine the moisture, ash, crude fiber, protein, fat, and carbohydrate. Briefly, the Kjeldahl method, as described by [15AOAC. Association of Official Analytical Chemists 18th ed. 2005.], was used for protein determination. Ash content was determined by using a muffle furnace at 600 ^oC for 3 hours, while moisture content determination was done by force air draft oven at 105^oC for 4 hours [15AOAC. Association of Official Analytical Chemists 18th ed. 2005.]. Crude fiber and fat were also determined using AOAC [15AOAC. Association of Official Analytical Chemists 18th ed. 2005.], while the Carbohydrate content and energy value were obtained by difference and Atwater factor (4,4,9), respectively.

Table 2
Formulation for cake production

A twenty-five-member panelist was used to assess cake samples' sensory attributes of appearance, aroma, taste, texture, and overall acceptability. The cake sample sensorial assessment was based on a 9-point hedonic scale quality analysis [16Ihekoronye AI, Ngoddy PO. Integrated food science & tech for the tropics 1985; 265-92.] with 9 representing liked extremely, and 1 representing disliked extremely. The panelists were individuals that are regular consumers of cakes and were neither sick nor allergic to any food. Necessary precautions were taken to prevent carryover of flavor during the tasting by ensuring that panelists rinse their mouth with water after each evaluation.

Data were obtained in triplicates. All results were subjected to analysis of variance (ANOVA) and mean separation was done with Duncan multiple range test at p <0.05 using the SPSS package.

The result of the physical properties of the cake presented in Table 3 shows that height, weight, and volume of the cake samples ranged from 2.7 to 3.9 cm, 39 to 50 g, and 625 cm³ to 1026 cm³, respectively. The queen’s cake samples top and bottom diameters had a range of 6.0-7.1 cm and 3.3 to 3.6 cm, respectively. The lowest value of height (2.7 cm), weight (39 g), and volume (625 cm³) was obtained when 50% of shea butter was incorporated as the shortening. Aside from when 100% shea butter was used, generally, height, weight, and volume decreased as the percentage of shea butter used increased.

The volume of the cake was highest (1026 cm³) for cake samples from flashed shea butter. Although Chinma et al. [17Chinma CE, Ingbian EK, Akpapunam MA. Processing and acceptability of fried cassava balls (“Akara-akpu”) supplemented with melon and soyabean flour. J Food Process Preserv 2007; 31: 143-56.
[http://dx.doi.org/10.1111/j.1745-4549.2007.00117.x] ] reported that weight and volumes of baked products are a function of the bulk density of flour, however, the result of the present study identified the composition of the shortening agent as a factor that influenced weight and volume. This behavior could be linked to the reduced ability of shea butter substitution with margarine level to retain air in the cake batter. There was no significant difference (p>0.05) in height and volume of cake produced from 100% shea butter and 100% margarine, whereas flashed shea butter cake had a significantly higher volume, which could be due to its higher ability to trap and retain air in the cake batter [18Chinma CE, Abu JO, Abubakar YA. Effect of tigernut (Cyperusesculentus) flour addition on the quality of wheat-based cake. Int J Food Sci Technol 2010; 45: 1746-52.
[http://dx.doi.org/10.1111/j.1365-2621.2010.02334.x] ]. Tireki [3Tireki S. Technology of cake production.Food engineering aspects of baking sweet goods 11^th ed. 2008; 104.] also opined that shortening used in cake production affects the volume, crumb tenderness, and evenness of the cell structure.

Value of height of cake samples obtained in the present work is comparable to that reported by Kiin-kabari and Banigo [19Kiin-Kabari DB, Banigo EB. Quality characteristics of cakes prepared from wheat and unripe plantain flour blends enriched with bambara groundnut protein concentrate. Europ J Food Sci Technol 2015; 3: 1-10.] on the quality characteristics of cakes prepared from wheat and unripe plantain flour blends enriched with Bambara groundnut protein concentrate where the height of the control of that study was recorded as 3.8 cm.

Table 3
Result of physical properties of cakes.

The moisture content, which is an index of keeping quality, differs significantly (p<0.05) for cake samples from 100% shea butter, 100% flashed shea butter, and 100% margarine. The ranges of moisture content of cakes were 13.7-17.3% in flashed shea butter shortening cake to margarine shortening cake, respectively. The range of moisture content (18.2-21.5%) for cake samples prepared from wheat and cocoyam flour blends reported by Alozie and Chinma [20Alozie YE, Chinma CE. Proximate composition, physical and sensory properties of cake prepared from wheat and cocoyam flour blends. J Food Res 2015; 4: 7-12.
[http://dx.doi.org/10.5539/jfr.v4n5p181] ] is higher than that obtained in the present study. This result could be due to the heat transfer property of shea butter, which allowed the removal of moisture during baking. Since cake samples produced from 100% margarine had a moisture value closed to that reported in the literature [20Alozie YE, Chinma CE. Proximate composition, physical and sensory properties of cake prepared from wheat and cocoyam flour blends. J Food Res 2015; 4: 7-12.
[http://dx.doi.org/10.5539/jfr.v4n5p181] ] (Table 4).

There was a significant difference in fat, protein, carbohydrate, crude fiber, ash content, and energy value for cake samples from 100% shea butter, 100% flashed shea butter and 100% margarine. The protein content of all cake samples significantly differs at p<0.05, with values ranging from 4.4-8.6% in samples flashed shea butter and margarine, respectively. The fat, crude fiber, and ash content increases with the increase in shea butter substitution. However, protein and carbohydrate content decreases with an increase in shea butter inclusion. Protein and carbohydrate content obtained in the present work was within the range of that reported by Alozie and Chinma [21Alozie YE, Udofia S, Lawal O, Ani IF. Nutrient composition and sensory properties of cakes made from wheat and African yam bean flour blends. J Food Technol 2009; 7: 115-8.], while the fat content obtained was higher than that reported in the literature [21Alozie YE, Udofia S, Lawal O, Ani IF. Nutrient composition and sensory properties of cakes made from wheat and African yam bean flour blends. J Food Technol 2009; 7: 115-8.]. This result could be due to the use of shea butter in the present study because fat content increases with the inclusion of shea butter. This fact could be linked to the fact that margarine has 80% fat in its composition [22Young N, Wassell P. Margarines and spreads.Food Emulsifiers and their applications 2008; 75.
[http://dx.doi.org/10.1007/978-0-387-75284-6_11] ]. And the energy value in kcal ranged from 440 to 472 for samples from margarine and flashed shea butter shortening, respectively.

Cake samples from 100%, 70%, and 60% margarine were not significantly different (p<0.05) in texture and overall acceptability as assessed by panelists. However, as the percentage of margarine in cake increases, the acceptability of cake samples’ texture increases. This could be because shea butter has been shown to have a lesser ability to entrap air in the mixing process with sugar, which is supposed to help in the development of its fluffiness. Also, there was no significant difference in taste and appearance for cake samples from 100%, 70%, 60%, and 50% margarine (Table 5).

When compared with cake produced from 100% shea butter, cake baked with flashed shea butter is more acceptable in texture, aroma, taste, appearance, and overall acceptability. This could be attributed to the change in flavor characteristics of shea butter brought about by the heating process that took place with the flashed shea butter. Concerning all sensory properties assessed by the panelists, cake samples produced from 60% Margarine and 40% Shea butter were most liked by the consumers. Cake samples with 100% shea butter had the lowest acceptability for texture, aroma, taste, appearance, and overall acceptability. This is in agreement with Fold [23Fold N. A matter of good taste? Quality and the construction of standards for chocolate in the European Union. Cahiers d’Economie et Sociologie Rurales 2000; 55/56: 92-110.], who reported a noticeable reduction in the acceptability of chocolate produced by using shea butter. Hence, the lowest acceptability of cake from 100% shea butter could be due to the significant difference in the flavor characteristics of the cake sample.

Table 4
Proximate composition of cakes.

Table 5
Sensory properties of cakes.