Prediction of the Mould-Free Shelf Life of Muffins

Abstract

In this article, the effect of commonly used ingredients in muffins (sugar, glycerol, potassium sorbate, acidic agent, salt), with and without ethanol surface spraying and pasteurization on the shelf life, was examined. Citric acid, sodium diacetate, and tartaric acid were used as acidic agents. The investigation was based on a statistical design of experiments. Using simple first order factorial designs, reliable models were constructed revealing the effects of the selected ingredients, and their interactions on the shelf life. The effectiveness of preservation ranked high to low as: (combination of citric acid, potassium sorbate, ethanol, and pasteurization), (combination of citric acid, potassium sorbate, and ethanol), (combination of citric acid and potassium sorbate), (combination of sodium diacetate and potassium sorbate), (combination of tartaric acid and potassium sorbate).

Keywords:

• Acidic agents
• Ethanol spraying
• Mould
• Muffin
• Pasteurization
• Shelf life

INTRODUCTION

Baked goods, containing principally flour are greatly affected by ingredients and additives included in a recipe.[1] Cake containing oils is, in the initial batter stage, a very complex emulsion of oil in an aqueous phase containing flour, starch, sugar, eggs, milk, and minor ingredients (baking powder, emulsifier, salt, etc). High ratio cakes made with liquid vegetable oil are aerated in the aqueous phase, and the form of stability is provided by egg yolk components and added surfactants.[2] Each basic ingredient in cakes performs a particular function.

Flour and eggs are fundamental structure builders providing strength and structure to the cake. They also function as water binders because their principal components (such as starch, protein, sugars, fat) have pronounced moisture-absorbing properties Starch, when added to the batter in amounts of 1 to 5 % increases batter viscosity and improves the volume symmetry, grain and texture of the resultant cake.[3] Sugar is the major flavoring, which further acts as a water binder (very effective at binding moisture) and tenderizer by diluting the flour proteins. Glycerol, a humectant, has the ability to absorb a great quantity of moisture and confers an increased soft-eating character to the crumb of cake. Vegetable oil is the primary tenderizer, flavoring and moistener of cake baking. Milk and water make the crumb texture finer and reduce lightness.

In addition, milk solids enhance flavor and function as water binder.[4] The functions of monoglycerides can be attributed to the reduction of the surface tension of oil providing a better dispersion of the oil phase and resulting in improved cake texture, crumb softness, and volume. They also decrease starch gelatinization in cakes leading to a better cake structure with improved tenderness.[5] Baking powder is a leavening agent produced by the mixing of an acid-reacting material (such as acid calcium phosphate or sodium acid pyrophosphate) and sodium bicarbonate. It is used to liberate carbon dioxide gas causing the necessary aeration and opening cake structure.[6]

Acidic agents are also frequently used in cakes. Citric acid CH₂(COOH)-COH(COOH)-CH₂(COOH) has not been used as a basic antimicrobial agent, however, it has activity against some moulds and bacteria. Citric acid and tartaric acid (CHOHCOOH)₂ can be used for adjusting the pH. Sodium diacetate has been recommended for use in baked goods, bread, candy, cheese spreads, meats, sauces and more, due to its microbial inhibitory action. It reduces the incidence of rope and growth of mould by decreasing the dough pH. It is said to have a preservative effect disproportionately large for its content of acetate.[7,8] Salt could affect significantly the Mould Free Shelf Life (MFSL), due to its powerful water-binding properties. However, there is a limit to the salt quantity because of its strong effect in flavor.[9] Potassium sorbate is a principal microbial and mould inhibitor extensively used in bakery products. It is effective at pH level up to about 6. At higher pH levels its effectiveness decreases significantly.[7,10,11,12] Ethanol, a strong bactericide has recently been used for its effective preservative action in bread. The addition of ethanol at levels 0.5 to 3.5 (g ethanol/100 g of cake) leads to a substantial extension of the shelf life of baked products. For a cake recipe to be correctly constructed, a good balance between the ingredients is needed.[12–14]

Spoilage from mould growth is much more likely to occur in cakes. The spoilage organoleptically or by pathogenic microbial growth is relatively small in cakes because of the nature of the ingredients used in cake making.[3,4] Although mould and mould spores are destroyed by the heat of the baking process, due to thermal inactivation, post-baking contamination occurs from the mould spores present in the atmosphere, during subsequent handling operations such as cooling, finishing, and wrapping.[10,15] It is evident that shelf life prolongation of cake is of great importance for the productivity and profitability of a company. Similar preservation methods to those used for bakery products can be used for muffins (type of cake). Mould inhibitors (such as propionates, sorbates, and ethanol), modified atmosphere packaging, pasteurization, freezing, etc. are mentioned in the relevant literature.[3,16,17,18]

Shelf life extension of cake and other baked products may be achieved using single ingredient or process change, or a combination of many alternative changes according to food legislation, ingredient availability and cost, consumer acceptance, and social trends. Manipulation of ingredients, which slow the rate of moisture loss during storage, such as sugar, glycerol, salt and preservatives, is a powerful tool, which could lead to a significant inhibition of cake microbial growth and therefore, sensible extension of mould-free shelf life could be achieved.[3,4,9,19]

This article aims to prioritize strategies that may be used in cake shelf life prolongation. Since muffin is a multicomponent mixture made by batter and additional optional ingredients (such as emulsifiers, fat, glycerol, milk, preservatives, ethanol, etc.), it is very difficult to investigate the influence of a single component on the shelf life in combination with the behavior of other components of the mixture. For that reason, five factorial experiments were designed.[20] Particularly, the effect of some selected common ingredients of cake and their interactions with other factors involved, on the mould-free shelf life was investigated in three experimental designs. The selected ingredients were sugar, glycerol, potassium sorbate, and an acidic agent (citric acid, sodium diacetate, and tartaric acid). The approved best recipe composition was investigated further (in higher degree experimental designs, by spraying the muffins with ethanol (0.5–1.5 g/100 g of muffin) and by applying spraying with ethanol and pasteurization simultaneously. This method facilitates the investigation by reducing significantly the number of required experiments, thus saving time and money. In addition, the models obtained may be used for predictions on the probable mould-free shelf life of muffins, within the variation intervals of factors (optimization parameter). In addition, complementary measurements of pH (a second optimization parameter), total microbial count and moisture were performed.

MATERIALS

Food grade basic (wheat flour, starch, sunflower oil, sugar, salt) and optional ingredients were used. The preservative used was potassium sorbate (Cheminova) and the acidic agents were citric acid (ADM), tartaric acid (ADM), and sodium diacetate (Boërniger). Ethanol was 96° food grade (Merck). Monoglycerides were used as emulsifier (Condea). Glycerol was food grade of 99.5% purity (Elton, Chemicals). The packaging material was a laminated film of 30 μm oriented polypropylene (OPP) and 21 μm polyvinyl dichloride PVdC (Mobil).

METHODS

Muffin Making Procedure

Muffin samples were prepared by mixing the chosen required and optional ingredients at proportions included in the formulae given in Table 1. The values of variables (design factors) are given in Table 2. At first the liquid ingredients were mixed for 15 minutes at the first speed of the mixer. Then, the solid ingredients were added and the batter is mixed for 2 minutes at the same speed. Accurately predetermined quantity of the mix (70 g) was deposited in paper-lined tins for muffins and placed in pans. The muffins were baked in an air oven at 180°C for 20 minutes. Then, they were cooled for 60 minutes at ambient temperature, removed from the baking pan, wrapped in plastic films, thermo sealed, and stored at room temperature. Five repetitions were performed for each experiment. The control was muffin prepared simultaneously (five repetitions) in the same oven under identical conditions with those of experimental design and its composition is given in Table 1. In the case of ethanol addition in muffin, the appropriate quantity of ethanol was sprayed on the whole surface of the muffin samples before wrapping. Then, the pouches were thermo sealed. When pasteurization was applied, the wrapped muffin samples were heated in an oven at 140°C for 45 minutes giving a core temperature of about 65–70°C.

Table 1 Composition ^a of cake samples in experimental design.

Ingredient	1^st	2^nd	3^rd	4^th	5^th ^c	Control
Flour	80	80	80	80	80	80
Starch	20	20	20	20	20	20
Water	75	75	75	75	75	75
Baking powder	3	3	3	3	3	3
Sunflower oil	33	33	33	33	33	33
Emulsifier	1	1	1	1	1	1
Eggs	30	30	30	30	30	30
Milk	12	12	12	12	12	12
Salt	1.5	1.5	1.5	variable	variable	1.5
Sugar	variable	variable	variable	variable	variable	75
Glycerol	variable	variable	variable	variable	variable
Potassium Sorbate	variable	variable	variable	variable	variable
Citric acid	variable	0	0	variable	variable
Sodium diacetate	0	variable	0	0	0
Tartaric acid	0		variable	0	0
Ethanol ^b	0	0	0	variable	variable
^ag/100 g of (flour + starch); ^bg/100 g of muffin; ^cmuffin samples were pasteurized.

Table 2 Coded and natural values of design factors.

	Design factors	Coded (−1,0, + 1) and natural levels ^a
Symbol	Ingredient	−1	0	+1	Jj
	Sugar	60.0	90.0	120.0	30.00
	Glycerol 1,2,3 design	1.0	4.00	7.0	3.00
	4,5 design	0.5	1.25	2.0	0.75
	Potassium sorbate	0.1	0.55	1.0	0.45
	Citric acid	0.1	0.55	1.0	0.45
	Sodium diacetate	0.1	0.55	1.0	0.45
	Tartaric acid	0.1	0.55	1.0	0.45
	Salt	1.0	4.00	7.0	3.00
	Ethanol ^b	0.5	1.00	1.5	0.50
^ag/100 g of (flour + starch); ^bg/100 g of muffin.

Examination of Muffin

Testing of the relative microbial free shelf life

The muffin samples were examined for visible signs of microbial growth on the crust every day. The microbial shelf life is defined as the period in days in which the spoilage caused by microorganisms was first observed. The shelf life was expressed in relation to the corresponding control.

Microbial analysis

Microbial analysis of bread samples has been carried out in triplicate. One g of the upper surface of a muffin sample was added to 10 ml of 0.85% sterilized saline, giving a dilution of 1:10. Sometimes, further dilution of 1:100, 1:1000, or 1:10,000 was needed. After homogenizing this solution, 1 ml was inoculated on plates, which contained tryptone glucose agar extract (Oxoid Ltd, UK) for total plate count and Sabouraud dextrose agar (Oxoid Ltd, UK) for yeast and moulds count. Then, the plates were incubated at 35°C, for 2 days for total plate count, and at 27°C for 5 days for yeast and moulds count. Finally, the number of colonies were counted and calculated by weight of muffin (Cfu/g muffin).

Measurement of pH

An electronic pH-meter was used (704, O Metrohm, Suisse). After calibration, using standard solutions at pH = 4 and pH = 7, each muffin suspension (10 g of ground muffin were added to 100 g distilled water and the dispersion was homogenized using a magnetic stirrer) was measured.

Moisture content determination

Water loss was determined by placing a weighed quantity of a part of muffin sample at temperature 130°C in an air oven for two hours, and it was expressed as moisture content: [(initial weight of muffin portion- weight of muffin portion after two hours)/initial weight] × 100. Triplicates were performed for each sample.[21]

Statistical Design of Experiments

In this article, five first order factorial designs[20] were applied with four or six design factors in each statistical experiment (3 designs with N = 2⁴ = 16 experiments each and 2 designs with N = 2⁶ = 64 experiments each). The coded and natural values of design factors are shown in Table 2. Five repetitions were performed for each experiment trial (design point). The coded values of the design factors are defined as:

(1)

where, x_j is coded value of the factor, is natural value of the factor, is natural value of the basic level, J_j is variation interval and j is the number of the factor. Both the relative shelf life (in relation to the corresponding control) of muffin samples and pH were selected as optimization parameters (y_i and pH_i , respectively). Faulty observations were determined with the aid of “Student's” t-test. The homogeneity of variances of trials was tested with Cochran's test and Fischer ratio. After calculating the factors coefficients from the results obtained, the insignificant factors were discarded using the estimated confidence interval. Then, the adequacy of the models was tested by the aid of the Fischer ratio.

RESULTS AND DISCUSSION

The values of real and relative bread MFSL regarding to the levels of selected ingredients of bread (sugar, salt, glycerol, potassium sorbate, and acidic agent) with and without ethanol surface spraying are given in 3–6. Five different factorial experiments were designed and carried out to investigate the effects of the design factors on the MFSL (optimization parameter).

Table 3 Shelf life of muffin with citric acid as acidic agent (first design).

Trial no.	x1 Sugar ^a	x2 Glycerol ^a	x3 K Sorbate ^a	x4 Citric acid ^a	Shelf life ^b (days)	Relative shelf life ^c (y1)
Control	75	0	0	0	7.3	1.00
1	120	7	1.0	1.0	31.8	4.36
2	120	7	1.0	0.1	26.8	3.67
3	120	7	0.1	0.1	13.1	1.79
4	120	1	0.1	0.1	12.7	1.74
5	120	7	0.1	1.0	20.0	2.74
6	120	1	0.1	1.0	18.4	2.52
7	120	1	1.0	1.0	19.3	2.64
8	120	1	1.0	0.1	17.7	2.42
9	60	7	1.0	1.0	14.4	1.97
10	60	1	1.0	1.0	10.7	1.47
11	60	1	0.1	1.0	9.3	1.27
12	60	1	0.1	0.1	8.2	1.12
13	60	1	1.0	0.1	10.2	1.40
14	60	7	0.1	1.0	10.6	1.45
15	60	7	0.1	0.1	8.7	1.19
16	60	7	1.0	0.1	10.4	1.42
Basic level	90	4	0.55	0.55	14.6	2.00
^a Natural values of factors (g/100 g flour + starch); ^b Mean, ± SD was in the range 0.5–1; ^c ± SD was in the range 0.08 – 0.18.

Table 4 Shelf life of muffin with sodium diacetate as acidic agent (second design)

Trial no.	x1 Sugar ^a	x2 Glycerol ^a	x3 K Sorbate ^a	x4 Na diacetate ^a	Shelf life ^b (days)	Relative shelf life ^c (y1)
Control	75	0	0	0	8.2	1.00
1	120	7	1.0	1.0	33.8	4.12
2	120	7	1.0	0.1	27.7	3.38
3	120	7	0.1	0.1	14.4	1.76
4	120	1	0.1	0.1	13.9	1.70
5	120	7	0.1	1.0	18.4	2.24
6	120	1	0.1	1.0	16.9	2.06
7	120	1	1.0	1.0	19.9	2.43
8	120	1	1.0	0.1	18.1	2.21
9	60	7	1.0	1.0	16.0	1.95
10	60	1	1.0	1.0	11.4	1.39
11	60	1	0.1	1.0	10.0	1.22
12	60	1	0.1	0.1	7.9	0.96
13	60	1	1.0	0.1	11.4	1.39
14	60	7	0.1	1.0	11.7	1.43
15	60	7	0.1	0.1	8.0	0.98
16	60	7	1.0	0.1	11.6	1.41
Basic level	90	4	0.55	0.55	15.6	1.90
^a Natural values of factors (g/100 g flour + starch); ^b Mean, ± SD was in the range 0.5–1.1; ^c ± SD was in the range 0.08–0.19.

Table 5 Shelf life of muffin with tartaric acid as acidic agent (third design).

Trial no.	x1 Sugar ^a	x2 Glycerol ^a	x3 K Sorbate ^a	x5 Tartaric acid ^a	Shelf life ^b (days)	Relative shelf life ^c (y1)
Control	75	0	0	0	8.3	1.00
1	120	7	1.0	1.0	33.6	4.05
2	120	7	1.0	0.1	26.0	3.13
3	120	7	0.1	0.1	14.5	1.75
4	120	1	0.1	0.1	14.0	1.69
5	120	7	0.1	1.0	19.2	2.31
6	120	1	0.1	1.0	16.4	1.98
7	120	1	1.0	1.0	20.3	2.45
8	120	1	1.0	0.1	18.6	2.24
9	60	7	1.0	1.0	15.6	1.88
10	60	1	1.0	1.0	11.3	1.36
11	60	1	0.1	1.0	10.3	1.24
12	60	1	0.1	0.1	8.1	0.98
13	60	1	1.0	0.1	11.5	1.39
14	60	7	0.1	1.0	11.9	1.43
15	60	7	0.1	0.1	8.5	1.02
16	60	7	1.0	0.1	11.6	1.40
Basic level	90	4	0.55	0.55	15.2	1.83
^aNatural values of factors (g/100 g flour + starch); ^bMean, ± SD was in the range 0.5–1.1; ^c± SD was in the range 0.08 – 0.20.

Table 6 Shelf life of muffin with citric acid and ethanol (fourth design).

Trial no.	x1 Sugar ^a	x2 Glycerol ^a	x3 K Sorbate ^a	x4 Citric acid ^a	x7 Salt ^a	x8 Ethanol ^b	Shelf life ^c (days)	Relative shelf life (y1)
Control	75	0	0	0	1.5	0	8.5	1.0
49	60	2.0	1.0	1.0	7	0.5	>50	>5.88
50	60	2.0	1.0	1.0	1	0.5	>50	>5.88
51	60	2.0	0.1	1.0	7	0.5	22	2.6
52	60	2.0	1.0	0.1	7	0.5	>50	>5.88
53	60	0.5	1.0	1.0	7	0.5	>50	>5.88
54	60	2.0	0.1	1.0	1	0.5	16	1.9
55	60	2.0	1.0	0.1	1	0.5	>50	>5.88
56	60	0.5	1.0	1.0	1	0.5	>30	>3.53
57	60	2.0	0.1	0.1	7	0.5	21	2.47
58	60	0.5	0.1	1.0	7	0.5	14	1.65
59	60	0.5	1.0	0.1	7	0.5	>50	>5.88
60	60	2.0	0.1	0.1	1	0.5	15	1.76
61	60	0.5	1.0	0.1	1	0.5	30	3.53
62	60	0.5	0.1	1.0	1	0.5	10.2	1.20
63	60	0.5	0.1	0.1	7	0.5	11.0	1.29
64	60	0.5	0.1	0.1	1	0.5	9.0	1.06
Basic level	90	1.25	0.55	0.55	4	1.0	>80	>9.41
^aNatural values of factors (g/100 g flour + starch); ^bg/100 g of muffin; ^cMean.

Where y_i (i = 1 … 5) is the shelf life relative to control (optimization parameter) and x_j (j = 1 … 8) is the design factor shown in Table 2. The difference between the two last designs is the pasteurization, which was applied only for the muffin samples of the 5^th design.

After processing these results discarding the insignificant factors, the following models for the MFSL were derived, expressed in relative values of significant factors:

(2)

(3)

(4)

The models of the fourth and fifth design could not be expressed by the relative equations y₄ and y₅ , since there were no results for the majority of muffin samples, which showed unlimited shelf life. The above equations are a useful tool for the estimation of the relative mould-free shelf life. Before using these equations, the coded values of factors must be calculated from Eq. (1) and data obtained from Table 2. Since the models are not linear, the relationship between the relative mould-free shelf life and the factors involved is more complicated, indicating that muffin MFSL is affected not only by the single factors but also by their interactions. The signs are generally positive, which means that the increase of any of these factors causes positive effect, leading eventually to an increase of the MFSL. This effect of the ingredients examined (sugar, salt, potassium sorbate, ethanol, acidic agents) is in accordance with that observed for bread and bakery products.[3,9,10,18,22]

The addition of the acidic agents at concentration ranging from 0.1 to 1 g/100 g of flour and starch was generally beneficial at extending muffin MFSL. It was observed in almost all cases an increase of MFSL with regard to the control, while the other three factors content remained in the selected interval range (3–5). This behavior of acidic agents could be attributed to the reduction of pH in the range 5.5–6, where potassium sorbate is more effective. In addition, these agents particularly Na diacetate and citric acid are considered mould and rope growth inhibitors.[3] It is evident that citric acid had a more significant inhibiting effect on microbial activities in comparison to Na diacetate or tartaric acid (Fig. 1). The higher positive synergistic effect of citric acid is, also, reflected in the higher values of coefficients of almost all the factors engaged (sugar, glycerol, potassium sorbate, citric acid), and the optimization parameters in the models (comparison of the parameter y₁ with y₂ and y₃ , respectively). Sodium diacetate and tartaric acid showed more similar inhibiting efficiency in the muffin MFSL, with Na diacetate being slightly more effective than tartaric acid. So, closer values of coefficients of almost all the factors involved (sugar, glycerol, potassium sorbate, acidic agent) and of the optimization parameters in the models (comparison of the parameter y₂ with y₃ ) were observed. The rank of the effectiveness of the acidic agents is illustrated in Fig. 1, when the rest factors are fixed at their maximum level. The interactions of citric acid, sodium diacetate and tartaric acid with potassium sorbate are shown in 2–4 respectively. It should be noticed the significant contribution of the three other factors, namely sugar, glycerol, and potassium sorbate to the improvement of MFSL, which is reflected in the values of their coefficients in the relative equations. Since the microbial inhibitory action of these ingredients has been established, their positive influence on MFSL was expected.[3,7,10,13,19]

Figure 1 Effect of acidic agent on the relative shelf life of muffin (sugar, glycerol, and K sorbate fixed at their maximum levels 120 g, 7 g, and 0.55 g, respectively, by 100 g of flour and starch).

Figure 2 Dependence of the relative shelf life of muffin (contour lines) on citric acid and potassium sorbate contents with sugar and glycerol fixed at their basic levels (90 g and 4 g, respectively, by 100 g flour and starch). Control shelf life 7.3 days. Coded values 1 to + 1 correspond to 0.1 to 1 g/100 g of flour and starch.

Figure 3 Dependence of the relative shelf life of muffin (contour lines) on Na diacetate and potassium sorbate contents with sugar and glycerol fixed at their basic levels (90 g and 4 g, respectively, by 100 g of flour and starch). Control shelf life 7.3 days. Coded values 1 to + 1 correspond to 0.1 to 1 g/100 g of flour and starch.

Figure 4 Dependence of the relative shelf life of muffin (contour lines) on tartaric acid and potassium sorbate contents with sugar and glycerol fixed at their basic levels (90 g and 4 g, respectively, by 100 g flour and starch). Control shelf life 8.3 days. Coded values 1 to + 1 correspond to 0.1 to 1 g/100 g of flour and starch.

The surface spraying of the muffins with ethanol (0.5–1.5 g/100 g of muffin) caused significant prolongation of their shelf life. Among the 320 muffin samples (64 statistical experiments), only 80 (25%) showed microbial spoilage and consequently definite MFSL The MFSL of these samples (with minimum sugar content and sprayed with ethanol 0.5 g/100g of muffin) are given in Table 6. Fifty percent of the total samples (160 samples sprayed with ethanol 1.5 g/100 g of muffin) had MFSL higher than 70 days. The rest—25% of the total samples (80 samples with maximum sugar content and sprayed with ethanol 0.5 g/100 g of muffin)—showed MFSL higher than 50 days. The beneficial effect of ethanol has been proved for a variety of baked goods.[3,16,18,22,23]

The 360 pasteurized and sprayed with ethanol (0.5–1.5 g/100 g of muffin) muffin samples had extremely high MFSL. The MFSL of the majority of the samples (90%) was higher than 100 days, indicating that the combination of pasteurization with ethanol addition in this recipe was extremely effective. Both methods, pasteurization and the use of chemical preservatives, have been extensively used in bakery products for MFSL extension.[6,18,22] The effectiveness of the investigated methods is depicted in Fig. 5.

Figure 5 Shelf life of muffins containing potassium sorbate as preservative with different methods.

The five different factorial designs were used also to investigate the effects of the (same as above for the MFSL) design factors on the pH of the muffins (Tables 1 and 2).

(5)

After processing these results discarding the insignificant factors, the following linear models for the pH were derived, expressed in relative values of significant factors:

(6)

(7)

(8)

The effect of acidic agent on the muffin pH is given in Fig 6. The pH in the fourth and fifth design remained almost constant at 7.5 and 7.35, respectively. This fact does not mean that some of the selected factors had no effect on the pH, but the models were very complicated due to the number of interactions (57 interactions). Thus, it was considered that a further investigation was worthless.

Figure 6 Effect of acidic agent on the pH of muffin (sugar, glycerol, and K sorbate fixed at their basic levels 90 g, 4 g, and 0.55 g, respectively, by 100 g flour and starch).

As far as the total microbial analysis is concerned, the results agree with the mould observations. None or extremely few colonies for yeast and mould were counted in each muffin at time less than its MFSL. The microbial number started to rise at times, exceeding the MFSL.

CONCLUSION

The mould free shelf life of muffins can be predicted using the equations derived by simple first order factorial designs. The factors investigated were sugar, glycerol, potassium sorbate, acidic agent, salt, ethanol surface spraying, and pasteurization. The models revealed the effect of the selected ingredients and their interactions on the shelf life. The combination of citric acid (an acidic agent), potassium sorbate (a conventional preservative), ethanol spraying of muffin surface, and pasteurization was proven to be the more effective preservation method, followed by the combination of citric acid, potassium sorbate, and ethanol spraying. The rank of acidic agents effectiveness in MFSL was citric acid > sodium diacetate > tartaric acid.