Investigation physical, chemical characteristics of functional drink based on apple juice and Aloe vera containing pigment of Echium Amoenum petal

Colors are used to create diversity and enhance the attractiveness of food. Pigment of Echium Amoenum petal in addition to having a natural pigment contain functional compounds such as anthocyanin’s and polyphenols. Research has shown that consuming foods rich in phenolic and anthocyanin compounds increases the body's ability to contract with the disease. Phenolic compounds are one of the most important compounds of fruits, vegetables and juices, and they have an important role in taste properties. It should be noted the phenolic compounds within the fruits, are anthocyanin’s, which play an important role in the color of the fruit. The compounds are soluble in water and are involved in water systems and have very beneficial effects on the health of the body. The use of phenolic compounds, antioxidants and anthocyanin’s in fruits such as pomegranate, strawberry, raspberries, cherries, cranberries, Echium Amoenum petal and etc., prevents the oxidation of LDL in blood (low protein density proteins). The other benefits of these compounds on the body can be cited to reduce cholesterol and anti-diabetic properties, increase prostatic antibodies to help improve heart disease, alzheimer's, breast cancer and intestinal cancer cells. Recently, many restrictions have been expressed by the international organization and research institutes on the use of artificial dye materials. On the other hand, consumers' desire to consume functional products has increased. The purpose of this study was to investigate the physical, chemical characteristics of functional drink based on apple juice and aloe vera containing pigment of Echium Amoenum petal.

In the first stage, the pigment of Echium Amoenum petal was extracted. In order to extract pigment from Echium Amoenum petal the maceration and solvent method was used. For this purpose, methanol and water in the ratio of 0.5 to 1.5 were used as the solvent system for extraction. 50 ml of solvent is added to 250 ml of laboratory erlenmeyer flask containing 5 g petals and then erlenmeyer is coated with a strong polyethylene coating to prevent solvent evaporation. The mixture was stored in a German WB22-memmert orbital oscillator at 50 °C for min 5 min until all the pigments are completely extracted. The extract was then separated from the petals by Watman's filter paper No. 1 and condensed by rotary evaporator Buchi water bath B-480 (Germany) at a temperature of 50 °C to Brix 60. The extracted pigments of Echium Amoenum petal were added to two types of beverages aloe vera and apple juice at concentrations of 5 and 10 percentages of volumetric, and the beverages were stored at two temperatures at 4 °C and 25 °C for 15 days. So, eight treatments were designed according to a completely randomized design. The pH test by pH meter, acidity was determined by titration with sodium hydroxide 0.1 N in the presence of phenolphthalein, the content of polyphenol compounds was evaluated using a spectrophotometer apparatus at a wavelength of 725 nm. Total amount of polyphenolic compounds in beverages in terms of gallic acid equivalents was calculated using the equation obtained from the standard curve and the results were expressed in mg gallic acid per milliliter of the extract. Measurement total anthocyanin level by using the differential pH method was measured by a spectrophotometer at 510 to 700 nm. Anthocyanin degradation index by using Spectrophotometer was obtained by dividing the absorption rate at 420 nm to absorbance at 520 nm. The amount of hydroxymethylfurfural contained in beverages was calculated in ppm by high performance liquid chromatography (HPLC). For this purpose, the samples were heated for 20 h. Then 1 ml of each sample was taken and 4 ml of distilled water was added to each of them along with 15% potassium ferrocyanide and 30% acetate. After stirring the samples were placed for 10 min in a 5000 rpm centrifuge and repeated twice. After centrifugation, the floating solution was removed each time, added to each other, and brought to a volume of 10 ml by distilled water. 5 ml of the sample was pour in the separating balloon, and added 5 ml of ethyl ether and mixed well. The bottom solution was discarded and the top solution was kept, and this was repeated. Finally, both solutions were poured together and 5 ml of distilled water was added to the solution. Samples were placed at temperature of 40 °C to remove diethyl ether, then the sample was filtered through 4.5 µm filter paper and injected into the HPLC Infinity 1200, made by Agilent, Germany. The amount of hydroxymethyl furfural in beverages in ppm and was calculated using the equation obtained from the standard curve (National Standard 19709, 2013). For data analysis, Duncan's one-way analysis of variance (ANOVA) was performed using Minitab 16 with 95% confidence.

Based on the results the samples containing aloe vera had lower pH and acidity than apple juice samples. Therefore, after 15 days of storage, the highest pH and the lowest acidity in apple juice containing 10% w/v of pigment were observed at 4 ˚C storage temperature. The amount of anthocyanin’s and polyphenolic compounds increased with increase pigment concentration in samples. The process of reducing these compounds in the beverages stored at 4 ˚C and containing apple juice during 15 days’ storage, was milder. Anthocyanin degradation index and hydroxymethylfurfural amount were lower than samples containing aloe vera juice and increasing the temperature and storage time increased these parameters. In other words, it can be said the effect of the type of drink, storage temperature and extract concentration can have a significant effect on the increase or decrease of all mentioned parameters. Over time, polyphenols content and anthocyanin decrease and over time the pH of the drinks decreased and the acidity increased, also, the amount of hydroxymethylfurfural during the time increased which was a sign of the destruction of sugars over time. In other words, it can be said, the effect the type of drink, storage temperature, and the concentration of the extract has been effective on increasing and decreasing all of the mentioned parameters.

The results of this study indicated that the apple juice stored at temperature 4 ˚C and containing 10% w/v pigment of Echium Amoenum petal had the highest amount of polyphenol, anthocyanin and the least anthocyanin degradation, acidity and pH changes, as well as the production of hydroxymethylfurfural over the course of time that it was known as the superior treatment and functional beverage.