Cite this article as:
Kinvan, E., Ozdal, T. (2022) “Improved domestic probiotic energy bar design by using sensory analysis methods”, Latin American Applied Research, 52(4) pp 387-392.
Abstract-- Today, studies have shown that probiotics have significant effects on health and can be used to prevent various diseases. However, the consumption of probiotic products is still not sufficient. Therefore, probiotic products should be multiplied and disseminated. In this study, it was aimed to develop a probiotic product with high nutritional value and energy level by using probiotic oatmeal, hazelnut, peanut, pistachio, almond, walnut and chocolate. The products produced as probiotic energy bars are designed in three different formulations. Then, sensory analyzes and microbiological analyzes were applied. Sensory analyzes were performed in triplicate and the results were given as mean ± standard deviation. The most preferred product formulation was selected using ranking tests and the profile of the products was examined using quantitative descriptive analysis from sensory analyzes. In microbiological analysis, the number of probiotic bacteria, the total number of bacteria, the number of molds and yeasts were determined and the suitability for consumption was evaluated. As a result, the produced probiotic energy bar was found suitable for consumption.
Keywords-- Probiotic, prebiotic, Lactobacillus plantarum, sensory analysis methods.
I. INTRODUCTION
Today, it has been determined that the groups of microorganisms that play a role in the production of some foods have important effects on health and can be used to prevent various diseases. Some bacteria in the microorganism groups whose effects on consumer health have been examined, although they are part of the normal flora, may also have probiotic properties. For this reason, the number and variety of probiotic products has increased, and accordingly, research and development activities in this direction have increased (Yücelşengün et al., 2020).
The idea of probiotics was first shaped in the early 20th century by Elie Metchnikoff, who is considered the father of modern immunology (Yılmaz et al., 2010). Probiotics were defined by Fuller in the 1980s as “nutrient supplements with live microorganisms that provide beneficial effects by improving the intestinal microbial balance of the host”. As it is understood, a person must have a healthy and functional gastrointestinal system in order to lead a healthy life. For these reasons, giving nutrients (prebiotics) or these microorganisms (probiotics), which are important components of microflora, has been an interesting treatment method in recent years (İsmailoğlu and Öngün Yılmaz, 2019; Markowiak and Ślizewska, 2017; Yılmaz, 2004).
Probiotics are live microorganism cultures or their metabolites that provide the development of the intestinal microflora of the host. They have beneficial effects on the digestive system, help their host to be healthy and grow rapidly (Akdeniz Oktay and Özbaş, 2020; Salçın and Ercoşkun, 2021). They take part in both the production and absorption of vitamins B and K. They facilitate the digestion of lactose and protein. They lower serum cholesterol levels and reduce allergy symptoms (Çelik et al., 2019; Nataraj et al., 2020; Sezen, 2013; Yılmaz, 2004).
Prebiotics are various dietary carbohydrates that cannot be digested and can be fermented by probiotic bacteria in the gut (Karabıyıklı and Donat, 2019). Thanks to the short-chain fatty acids formed as a result of fermentation, a pH environment suitable for probiotics but not suitable for pathogenic bacteria is formed. At the same time, they stimulate the selective growth of these bacterial groups and create energy sources. They are calorie-free, increase the absorption and bioavailability of minerals such as Ca and Mg, and reduce the risk of developing colon cancer (Çelik et al., 2019; Özden, 2005; Vera et al., 2021; Yılmaz, 2004).
In recent years, increasing interest in probiotics and prebiotics in the scientific, health care and public fields and microbiome research has expanded the public perception of microorganisms to a more rational perspective that supports the understanding of the beneficial roles of microorganisms in human health. This has improved functional food production by adding probiotics and prebiotics to foods (Cunningham et al., 2021; Granato et al., 2020; Manzoor et al., 2022; Sağdıç et al., 2004).
In this study, a functional food was developed using prebiotics and probiotics. First of all, Lactobacillus plantarum probiotic bacteria was immobilized on oatmeal that have also prebiotic properties due to its high β-glucan content, and then a new energy bar was developed with this probiotic oatmeal.
II. METHODS
A. Materials
Plate Count Agar (PCA) (Millipore, Massachusetts, ABD) medium was used for total aerobic mesophilic bacteria, De Man Rogosa and Sharpe Agar (MRS) (Millipore, Massachusetts, ABD) medium was used for Lactobacillus plantarum count, and Dichloran Rose Bengal Chloramphenicol Agar (DRBC) (Millipore, Massachusetts, ABD) medium was used for total mold and yeast count analyzes.
B. Sample preparation
After it was decided to produce a probiotic energy bar as a product, 3 different formulations were produced using a local and brand-registered original probiotic oatmeal (ProAt, Simbiyotek Inc., Istanbul, Turkey), dates, tahini (Taskale, Emek Gıda Co., Konya, Turkey), walnuts, hazelnuts, peanuts, pistachios and almonds (Tugba Kuruyemis Co., Aydin, Turkey) and chocolate (Ulker Chocolate Inc., Istanbul, Turkey).
As the components that will create the main differences in the three formulations, the components that will both keep the structure together and shape the taste of the product were determined as date and tahini. Therefore, while the amounts of other ingredients are kept constant in all three formulations, the amounts of dates and tahini are variable. Then, since the daily ProAt consumption limit was 2.5 g, 30 g products containing 2.5 g of ProAt were produced.
For the first formulation, 112.5 g of ProAt, 585 g of fresh dates, 67.5 g of pistachios, 90 g of peanuts, 225 g of tahini, and the remaining walnuts, hazelnuts and almonds were weighed 90 g each and mixed. The resulting mixture was shaped and products were formed. While production was made with 450 g dates and 360 g tahini in the second formulation, 360 g dates and 450 g tahini were used in the third formulation. Then the products were covered with melted chocolate as shown in Fig. 1.
After the products are fully ready, they are individually packaged with aluminum foil and stretch in an airtight manner.
C. Microbiological analysis
Lactobacillus plantarum, total bacteria, mold and yeast counts were examined in all three formulations (Húngaro et al., 2014). Analysis were performed in triplicate and results were given as mean ± standard deviation.
D. Sensory analysis
Ranking test was performed with 12 trained panellists from Istanbul Okan University. They ranked 3 random-digit coded products according to their preference for appearance / color, odor, texture, taste and general preference. For each attributes, the products were ranked from the most liked product to the most disliked product (Ekman et al., 2020; Whelan, 2017).
The Quantitative Descriptive Analysis were perfor-med with 12 trained panellist from Istanbul Okan University. Panellist described and worked on the reference product, for 40 hours in pre-panels. A total of 30 parameters in the categories of appearance, odor, taste / aroma and texture were described. Product evaluations started with the reference sample. Here, unlike the ranking tests, three samples were presented to the panelists separately, not together. After the evaluation of one sample, the other sample was given to the panelists.
Figure 1: Probiotic energy bars.
Initially, the reference sample was evaluated as common. For each parameter, a joint score between 1 and 7 was made. The other two samples were then individually evaluated by the panelists. After the evaluations of the products were completed, the panel forms were collected and evaluated. Statistical analysis were performed to understand the significant differences between products for 30 parameters (Gámbaro and McSweeney, 2020; Kilcast, 2004; Lawless and Heymann, 2010).
E. Statistical analysis
Mean and standart deviation of microbiological analysis results were calculated.
Analysis of variance, Friedman test and LSD-Rank analysis were used for evaluating ranking test results. For evaluation of quantitative descriptive analysis, one way analysis of variance (ANOVA) and Duncan post-hoc tests were performed for determination of statistically significant differences between samples (p < 0.05) for all parameters by using IBM SPSS Statistic Version 25 program (Feng et al., 2017; Hoffman, 2019; King, 2010; MacKenzie, 2013; Williams and Abdi, 2012).
Firstly, required ranking totals (p<0.05) at 5% significance level was determined from the Kramer - Twigg table according to the number of panelists and formulations for analysis of variance. The 18 - 30 and 19 - 29 values of required ranking totals are determined from the Kramer - Twigg table. Then, by comparing these ranking totals with the ranking totals obtained from the products, it is determined whether there is a significant difference between the products according to the categories of appearance / color, odor, structure, taste and general preference (King, 2010).
In addition, the Friedman test is a test used to check whether there are significant differences in the 5 categories by using ranking totals according to Fk value. The Fk value was calculated by using
Fk=12/J*P*(P+1)*(R12+...+RP2)-3*J*(P+1) (1)
equation. When the F value was less than the Fk value, there was no statistically significant difference (p<0.05) between the products in terms of general preference. However, when the F value was greater than the Fk value, a statistically significant difference (p<0.05) was found between the products in terms of general preference (Hoffman, 2019).
According to the Friedman test results, LSD-Rank analysis was applied in the categories with statistically significant differences. Thus, it was determined which products caused the difference. The equation
| Ri - Rj | ≥ 1.96√N*k*(k+1)/6 (2)
used here showed that there were differences between the products. However, the equation
| Ri - Rj | ≤ 1.96√N*k*(k+1)/6 (3)
used here showed that there was no differences between the products (Williams and Abdi, 2012).
III. RESULTS
A. Evaluation of microbiological analysis results
The amount of Lactobacillus plantarum required in a 30 gram Probiotic Energy Bar containing 2.5 g ProAt was calculated as
2.5*1300000/30=1.08x105 CFU/g. (4)
The data obtained after counting are shown in Table 1.
B. Evaluation of sensory analysis results
In the ranking tests, it was checked whether there were significant differences in 5 categories: appearance / color, odor, texture, taste and general preference. For appearance & color, the ranking total of the sample 371 is 18, the ranking total of the sample 512 is 23, and the ranking total of the sample 930 is 31. For odor, the ranking total of the sample 371 is 25, the ranking total of the sample 512 is 21, and the ranking total of the sample 930 is 26. For the structure, the ranking total of the sample 371 is 19, the ranking total of the sample 512 is 23, and the ranking total of the sample 930 is 30. For taste, the ranking total of the sample 371 is 19, the ranking total of the sample 512 is 28, and the ranking total of the sample 930 is 25. For the general preference, the ranking total for the sample 371 is 18, the ranking total for the sample 512 is 28, and the ranking total for the sample 930 is 26.
When it was checked whether the ranking totals for appearance / color were not between 18 and 30 according to the Kramer - Twigg table for analysis of variance, ranking totals for appearance / color were not between 18 and 30. For this reason, the 19 - 29 range has been checked for appearance / color. While 23 is in this range but 18 and 31 is not in this range. So there is significant differences for appearance / color. The 371 coded sample’s appearance / color was the most liked sample and the 930 coded sample’s appearance / color was the most disliked sample. On the other hand, when it was checked whether the ranking totals for odor, structure, taste and general preference was between 18 and 30, they was between 18 and 30. So there is no significant differences for odor, structure, taste and general preference.
Fk value was calculated as 6.17 for Friedman test. Probiotic Energy Bar F value is 7.17 for appearance & color, 1.71 for odor, 5.17 for texture, 3.50 for taste and 4.67 for general preference. Since the F value calculated for only appearance & color is greater than the Fk value, a statistically significant difference was observed between the products only for appearance & color.
According to the calculations made with equations 2 and 3, in the LSD-Rank analysis, 9.6>5 for the 23 - 18 ranking totals, 13>9.6 for the 31 - 18 ranking totals, and 9.6>8 for the 31 - 23 ranking totals in the appearance & color category were calculated. The result 13>9.6 showed that there was a difference between the 371 and 930 coded products.
In the ANOVA and Duncan post-hoc test inner color density, homogeneity, surface smoothness, wholeness, brightness, chocolate odor, tahini odor, date odor, oat odor, nut odor, oil odor, date aroma, chocolate aroma, tahini aroma, oat aroma, nut aroma, oil aroma, rancidity, bitterness, sweetness, saltness, after taste, hardness, chewiness, oiliness, dissolve in the mouth, roughness, moistness, fibrousness and adhesiveness parameters were evaluated.
When the significant values in the ANOVA table were examined, a statistically significant difference (p<0.05) was found in 21 of the 30 parameters. As significant values for Inner color density, homogeneity, surface smoothness, wholeness, chocolate odor, tahini odor, date odor, oat odor, nut odor, oil odor, date aroma, tahini aroma, oat aroma, nut aroma, rancidity, bitterness, after taste, hardness, chewiness, roughness and adhesiveness parameters were statistically significant difference (p<0.05) was found.
In the Duncan post-hoc test and statistically significant difference (p<0.05) was observed for sweetness and dissolve in the mouth parameters, in addition to others. Duncan post-hoc test results table is shown in Table 2.
IV. CONCLUSION AND DISCUSSION
When the results obtained from the analysis
of the products were evaluated, according to the Kramer - Twigg table for the
analysis of variance, the appearance/color of the 371 coded sample was the most
popular in terms of appearance/color, while the appearance/color of the 930
coded sample was the least liked. The reason for this result is thought to be
due to the fact that the color difference between the two products with the
highest amount of difference in the amount of light and dark colored raw materials
such as tahini and dates is very evident and the dark color provides an
advantage. On the other hand, it is thought that the reason why there is no
significant difference for other features (smell, texture, taste and general
preference) is that these