Application of Microencapsulation Technology in Mushroom Powder Cake Processing

In this study, Lentinus edodes (or mushroom) powder and carrot juice were used as raw materials to prepare a new type of nutritious cakes. Microencapsulation was applied in embedding vitamin C to prevent the loss of this vitamin during baking at high temperatures. The most suitable addition amount of each materials was optimized via single-factor test and response surface analysis. The optimal microencapsulation of shiitake mushroom powder with carrot juice required 10 g of mushroom powder, 35 g of soft sugar, 50 mL of carrot juice and 160 g of egg white. The cake prepared herein was rich in nutrient and exuded a unique flavor. This cake was prepared via modern processing technologies and efficient detection techniques. Microencapsulation not only improves the nutritional value of traditional flour products but also expands the scope of research on food processing technologies. Practical applications Lentinus edodes is a nutritious food with low fat content and rich in polysaccharides and vitamins. Consumption of this mushroom improves immunity, lowers blood pressure, and prevents the development of various types of cancer. Ground L. edodes powder is also called mushroom powder, which has the same nutrient composition and efficacy as L.entinus edodes. Carrots produce a fresh aroma, and the large amounts of β -carotene in carrots improve the nutritional value of carrot-based food and also exert beneficial effects, such as preventing xerophthalmia, night blindness, and oral ulcer. A new cake made of carrot juice and mushroom powder can effectively improve the nutritional and economic values of carrot and mushroom powder. However, vitamin C easily loses its function at high temperatures. In this study, vitamin C was microencapsulated to reduce its outflow. The purpose of this study was to expand the applications of microencapsulation technology, provide a scientific basis for the production of nutritious functional foods, and offer new research ideas for the development of new cakes.


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Pre-experimental operation steps Preparation of microcapsules 111 First, 0.75 g of sodium alginate was added to 50 g of purified water. The mixture was stirred 112 until clear and set aside for later use. Afterward, 0.2 g of vitamin C tablet was ground into powder 113 and then added into the sodium alginate solution. Subsequently, 2 g of calcium lactate was added in 114 50 g of purified water. The mixture was stirred until clear, and set aside for later use. Finally,the 115 mixed solution of sodium alginate and vitamin C was dripped into the solidified calcium lactate 116 solution by using a dropper to form spherical microcapsules.

Preparation of carrot juice
117 Carrots were cleaned with water and then cut into pieces, several of which were put in a juicer. 118 Twice the volume of purified water was poured into the juicer, and then the carrots were squeezed.

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The juice was set aside for later use.

Blending of batter
120 L. edodes powder and cake powder were mixed at a certain proportion. An appropriate 121 volume/amount of carrot juice, soft sugar, edible oil, baking powder, and beaten egg yolks and egg 122 white were added to the powder. The mixture was evenly mixed to obtain the batter.
Injection molding 123 The batter was poured into the cake crust, accounting for about 2/3 of the cake crust. An 124 appropriate amount of microcapsules was added, and the batter was mixed well.

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The oven was preheated at 180 ℃ for about 5 min. Afterward, the cake was placed in the oven 126 at 180 ℃ and baked for 20 min to obtain the finished product.

Experimental design
Single-factor tests 127 According to the results of our preliminary experiment, a single-factor experiment was 128 conducted with the addition amount of mushroom powder, soft white sugar, carrot juice and egg 129 white as the factors.  Product quality evaluation 159 Ten professionals were selected to evaluate the cake on five sensory indexes of color, 160 appearance, taste, organization, and smell.Their scores were averaged. The criteria are listed (Table   161 2). where m 0 is the mass of the mold, m is the mass of the finished product after cooling for 30 min, V 1 173 is the original volume of millet, and V is the volume of cake after adding millet. (Volume was 174 measured via the millet method [18].)Each sample was measured in parallel three times, and the 175 specific volume score of the cake was taken as the average value.

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The specific volume scores of the cake according to GB/T 24303-2009 "Inspection of grain 177 and oils: Method for cake-making of wheat flour-Sponge cake" are summarized (Table 3).

Results and analysis
Single factor experiment results Optimization of L. edodes powder addition amount 182 The physicochemical and sensory indexes of different addition amounts of L. edodes powder (5,   183 10, 15, 20, and 25 g ) were measured to determine the optimal addition amount of the mushroom 184 powder to add (Fig. 2). The specific volume scores and vitamin C contents initially increased and then decreased as 190 the amount of mushroom powder added increased (Fig. 2). The specific volume score was the 191 highest when 10 g of the mushroom powder was added. At this moment, the cake had the best 192 fluffiness and softest taste. The vitamin C content was the highest when 15 g of the mushroom 193 powder was added. Therefore, microencapsulation effectively embedded the vitamin C of the cake.

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In spite of the high temperature at which the cake was baked, its vitamin C content was preserved 195 to the greatest extent, indicating that vitamin C was protected and a large loss of vitamin C content 196 was prevented. The sensory scores initially increased and then decreased as the addition amount of 197 L. edodes powder increased. The sensory score was the highest when the addition amount of the 198 mushroom powder was 10 g, but it gradually decreased.L. edodes powder itself has a unique flavor, 199 but it does not taste good. When the addition amount was less than 10 g, the unique flavor of L.
200 edodes was not obvious. However, the cake tasted bad and the smell of the mushroom was strong 201 when excessive amounts of the mushroom powder were added. Therefore, the optimal addition 202 amount of L. edodes powder was 10 g. The specific volume scores and vitamin C contents initially increased and then decreased as 210 the addition amount of soft sugar increased (Fig.3). The specific volume scores and vitamin C 211 contents were the highest when 35 g of soft sugar was added. However, microencapsulation had 212 negligible effectes on the specific volume scores and vitamin C contents of the cake. Nevertheless, 213 the cake had the best fluffiness. The microencapsulation technology was adopted to preserve the 214 vitamin C content of the cake as much as possible.The cake was microencapsulated , to protect 215 vitamin C effectively and prevent large losses of this vitamin at high temperatures. The sensory 216 score was highest when 35 g of soft sugar was added, but it gradually decreased. Adding soft sugar 217 increased the sweetness of the cake and improved its taste. When the addition amount of soft sugar 218 was less than 35 g, the sweetness of the cake was low and it was tasteless. When the addition amount 219 exceeded 35 g, the sweetness increased, but the cake felt greasy and it tasted bad. Therefore, the 220 optimal addition amount of soft sugar to add was 35 g. The specific volume scores initially increased and then decreased as the addition volume of 228 carrot juice increased; by comparison, the vitamin C content of the cake increased. The specific 229 volume score was the highest, and the cake had the best fluffiness and softest taste when the addition 230 volume of carrot juice was 40 mL. The vitamin C content was the highest when the addition volume 231 was 60 mL. Thus, microencapsulation effectively embedded vitamin C, and protected it at high 232 temperatures, thereby preventing large losses of vitamin C during baking at high temperatures.The 233 sensory score of the cake initially increased and then decreased as the addition volume of carrot 234 juice increased. When the addition volume was 50 mL, the sensory score was the highest, but it 235 gradually decreased. Adding carrot juice made the cake more fragrant and improved its taste. When 236 an insufficient volume of carrot juice was added, the fragrant taste of carrot juice was not obvious 237 and the carrot flavor could not be tasted. By contrast, when excessive volumes of carrot juice were 238 added, the cake tasted heavy, and the people we asked to taste it did not like the cake. Therefore, 239 the optimal addition volume of carrot juice to add was 50 mL. softer, and with a better taste. When the addition amount of egg white less than 160 g, the finished 255 cake was not fluffy. When too much egg white were added, the cake was too fluffy and tasted bad.

Optimization of addition amounts of egg white
256 Therefore, the optimal addition amount of egg white to add was 160 g.  (Table 4).  267 a "* * *" means extremely significant, "* *" means very significant, "and" * "means significant."

Results of response surface tests
The order of importance of the influencing factors was as follows: the volume of carrot juice > 291 the amount of mushroom powder > the amount of soft sugar > the amount of egg white (Table 5).

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The F-value of Y 2 was 40.21 (p < 0.0001), indicating that model Y 2 was extremely significant. white and the addition volume of carrot juice to add were 10, 35, and 160 g and 50 mL, respectively.

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The actual sensory scores were 93, and vitamin C content was 92.451 mg/100 g. The deviation 367 between the predicted and actual values was small, confirming the effectiveness of the models.  Fig.2 Effect of mushroom powder on cake quality. S3 Fig.3 Effect of the amount of soft sugar on cake quality. S4 Fig.4 Effect of the volume of carrot juice on cake quality. S5 Fig.5 Effect of the amount of egg white on cake quality. S4 Table. Experimental results of response surface analysis.The table shows the analysis results of the single-factor test.