Inhibition of non-enzymatic browning and color behavior in functional cinnamon jelly candies during storage

Introduction: Soft confectionery products known as pastilles are in the form of edible jelly and jelly candies, which are more preferred by children compared to other types of candies, because they are easily swallowed, shiny appearance, delicious taste and have an attractive color (Amjadi et al. 2018). There are different forms of candy, some are hard and some are soft. Soft jelly candies have a soft texture and are processed by adding gelling agents such as gelatin, carrageenan and agar (Maras et al. 2022). The health of jelly candies has been questioned due to the high content of absorbable carbohydrates, low fiber, as well as low protein, vitamins or antioxidants (Sedno-Pinos et al. 2020). In general, first qualitative feature of food that is noticed by the consumer are its appearance and color. Color is one of the important aspects of food appearance and affects their acceptability by consumers, which actually shapes the perception of food taste. The Maillard reaction starts with condensation of amino groups of proteins, peptides and amino acids with carbonyl groups present in reducing sugars and in final stage leads to the formation of colored macromolecular compounds (Lund and Ray, 2017). Cinnamon mainly contains caffeic, vanillic, gallic, ferulic, coumarin, proanthocyanidins B1 and B2 and cinnamic acid (Błaszczyk et al., 2021). Many studies have shown the therapeutic effects of cinnamon, including antioxidant, antidiabetic, antimicrobial, antiviral, antifungal, antitumor, antihypertensive, antifat, digestive tract protection and immune system modulation (Hajimonfarednejad et al., 2019). The unique beneficial properties of cinnamon can lead to the improvement of texture, consistency and stability during production and even increase the preservation of food (Jahanbakhshi and Ansari 2020). Also, due to the antimicrobial and antioxidant properties of cinnamon, it is widely known as a safe food preservative (Darwash et al. 2023). Some studies reported that cinnamon has been widely used as a flavoring agent in traditional as well as modern foods and beverages (Hilal et al. 2014).
This research was carried out with the aim of the effect of cinnamon powder in jelly candy to create the desired color and prevent non-enzymatic browning during production and storage.
Materials and methods: To prepare cinnamon jelly candy, components were weighed with specific percentages (Figure 1). Cinnamon powder was added to the formulation at 5 levels (0, 0.125, 0.25, 0.375 and 0.5 g per 100 g of samples). First, components were weighed and then added to water at 80°C and mixed well with a magnetic heater. The prepared candy syrup was poured into hemispherical silicone molds (diameter of 37 mm and height of 15 mm) and they were placed in refrigerator for 2 h to set the gel. To prepare cinnamon jelly candy, the components were weighed with specific percentages (Figure 1). Cinnamon powder was added to the formulation at 5 levels (0, 0.125, 0.25, 0.375 and 0.5 g per 100 g of samples). First, it was weighed and then added to water at 80°C and mixed well with a magnetic heater. The prepared candy syrup was poured into hemispherical silicone molds (diameter 37 mm and height 15 mm) and placed in the refrigerator for 2 h to seal the gel. The samples were removed from the molds and dried and the humidity reached the standard range (about 21-20%) for 48 h at 30 °C. The necessary bags were packed within 4 months. Qualitative tests Determination of pH: National Standard No. 2682 was used to measure the pH of the samples (Iran National Standard No. 2682 1395). Determination of moisture content: National Standard No. 2682 was used to measure the moisture content of the samples (Iranian National Standard No. 2682 2015). Preparation of digital images and determination of color indices: Digital image method was used to measure the initial color of the samples and its changes during the storage life. The samples were placed in the Hunterlab simulator and the pictures were taken with a Canon digital camera perpendicular to the samples (with a distance of 30 cm). The images were transferred to Photoshop software and their color indices (L⁎, a⁎, b⁎) were determined through RGB (Dudley et al. 2007). Next, overall color change (ΔE), chroma index (C) or saturation index (SI), hue angle (Hue), browning index (BI) and whiteness index (WI) were calculated (Lin et al. 2009). The Factorial experiment was in a completely random design and from variance analysis at probability level of 5% (P ˂ 0.05) was used. For comparing the means with Duncan's multi-range test by SAS software (version 9.1) and graphs carried out with Excel software.
Results and discussion: All tested samples (containing cinnamon powder) have been compared with control (without cinnamon powder). The results showed that color indices of different cinnamon samples had a significant difference (P < 0.05) during storage. Brightness of color space (L*) among the samples with different amounts of cinnamon powder, compared to the control, always displayed a decreasing trend (darkness) during months of storage. Even in jelly candies with a certain amount of cinnamon powder, there was a decrease in brightness. Redness of color space (a*) among the control samples during storage had an increasing trend (redness along with reactions of browning), but in the samples with the same and different amounts of cinnamon powder, compared to the control, during storage period, it was always displayed a decreasing trend (controlling the redness of the samples or turning green). Yellowness of color space (b*) among the control samples had an increasing trend (yellowing) during storage, but in the samples with the same and different amounts of cinnamon powder, compared to the control, there was always a decreasing trend (bluing) during storage. Seen in Table 1, it was concluded that jelly candies containing 0.375 g of cinnamon powder in 100 g of samples during storage period showed good results in terms of statistics. Also, indices such as overall color change index, chroma index, hue angle were investigated on the samples. The browning index indicated that by increasing the amount of cinnamon powder in jelly candies from 0.125 g to 0.5 g, inhibitory power of browning reaction greatly was increased. Cinnamon has a spicy and intense taste with red or dark brown color. The aroma and flavor of cinnamon is due to the aromatic essential oil, which constitutes 0.5-1% of its compounds and there is a correlation between the dark brown color and cinnamon coumarin (Faraji et al., 2023). As a result, this feature of cinnamon was used to produce natural color in jelly candy. In the prevention of non-enzymatic browning, from investigation of Figure 2 was seen that color of jelly candy in control samples reached from 91.9 in first month to 184.78 in fourth month, which was accompanied by an increase of 50.2%. A completely opposite situation was observed in jelly candies with different amounts of cinnamon powder. So that in the samples with 0.125, 0.25, 0.375 and 0.5 g of cinnamon powder, from first month to the fourth month of storage, browning index had been decreased respectively 44.7, 63.4, 48.8, 52.4%. Whiteness is another important index in measuring the amount of product color changes towards whiteness or cloudy (Lin et al., 2009). The whiteness index is another important index in measuring the amount of product color changes towards whiteness and turbidity (Lin et al. 2009). As can be seen in Figure 3, the whiteness index of the control sample (without cinnamon powder) in the first month went from 41.85 to 31.12 during four months of storage, with an increase of 25.64% in turbidity or with a decrease of 64%. 25% whiteness was included. In jelly candies with different amounts of cinnamon, the rate of cloudiness has progressed slowly during the months of storage. So that in the samples with 0.125, 0.25, 0.375 and 0.5 g of cinnamon powder, from the first month to the fourth month, the whiteness index is 21.51, 16.18, 13.33, respectively. It had decreased by 2.16%. From the experiments, it can be concluded that by increasing the concentration of cinnamon powder in jelly candies, turbidity can be easily controlled.
Conclusion: Cinnamon powder concentrations were used in jelly candies to control non-enzymatic browning reactions. Investigating browning index of different treatments showed that jelly candies containing cinnamon powder had a high inhibitory-ability on non-enzymatic browning reactions. These reactions mainly inhibit through blocking of amino agents. Another important index in measuring the amount of product color changes towards whiteness and cloudy was the whiteness index, which in jelly candies with different amounts of cinnamon powder, the rate of cloudy had progressed slowly during months of storage.