Encapsulation of black carrot extract in pectin and/or Na-aljinat beads by cold gelation

The potential of food industry usage is quite high for the black carrot, which contains a variety of phytochemicals such as phenolics, α-tocopherol, polyacetylene and carotenoid, and its consumption increasingly mounts up, being rich in anthocyanins. There seems to be increasing trends towards healthy-life by concecious consumers. Addition of the functional components to the food products are needed in order to improve the nutritional value described as useful for health and inoovative. These compounds are very sensitive against the environmental, gastrointestinal and processing conditions, and they can be quickly inactivated. When looking at the literature, it is observed that microencapsulation formed with the inclusion of bioactive components into a coating material is used to overcome this type of difficulties, and at the same time, unwanted interactions with the food matrix is blocked, also providing the controlled release of the encapsulated compound. In this study, microencapsulation was carried out with cold gelation method. 2% pectin, %2 alginate, 1% pectin-1% alginate solutions were used as a coating material, different concentrations of (1%, 0.5%, 0.25%) black carrot extract was used as the active material. Active substances in significiant concentrations were added to each of 2% alginate, 2% pectin, 1% pectin-1% alginate solutions as separately, and were homojenized by stirring on a magnetic stirrer. Finally, 0.02% sodium azide was added to the obtained mixtures due to antimicrobial property. Each mixture that has been prepared was dropped into a 3% CaCl2 solution with a 5 mL syringe and kept for a while for the purpose of protect the structure of gel. After that, they were filtered and were stored in top glass jar for a period of 4 weeks at +4 °C jar. In this study was obtained capsules containing 1%, 0.5%, 0.25% black carrot extract coated with 2% pectin; capsules containing 1%, 0.5%, 0.25% black carrot extract coated with %2 alginate; 1%, 0.5%, 0.25% black carrot extract coated with 1% pectin-1% alginate. And also, capsules without active material coated with 2% pectin, 2% alginate and 1% pectin-1% alginate was obtained. 15 g of capsules which are containing 1% black carrot extract as active material and having 2% pectin, 2% alginate and 1% pectin-1% alginate as coating material were stored at 4°C for 4 weeks by being added separately into 50 g yoghurt. Encapsulation efficiency of the samples and the light microscope images were examined. For 1-week periods, change in the color, the antioxidant capacity with CUPRAC and ABTS methods and in the total anthocyanin capacity in all samples were analyzed during storage period. The goal of the storage study was to examine the effect of the storage time on the microencapsulated black carrot extract that was added to the product. At the end of the 4-week storage period at +4°C, while 36.42% reduction was detected with CUPRAC method in the total antioxidant capacity of the encapsulated product containing 1% black carrot coated with 2% pectin, this value was determined as 62.40% for the sample that contained 0.5% black carrot extract, and as 56.75% for the sample that contained 0.25% black carrot extract. At the end of the 4-week storage period at +4°C, while 67.94% reduction was detected with CUPRAC method in the total antioxidant capacity of the encapsulated sample containing 1% black carrot in which 2% alginate was used as the coating material, this value was determined as 52.17% for the sample that contained 0.5% black carrot extract, and as 62.37% for the sample that contained 0.25% black carrot extract. Reduction in the total antioxidant capacity of the encapsulated samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 1% pectin-1% alginate coating material at the end of the 4-week storage period at +4°C was stated as 48.50%, 48.56%, 68.65%, respectively with CUPRAC method. At the end of the 4-week storage period at +4°C, while 17.06% reduction was detected with ABTS method in the total antioxidant capacity of the encapsulated product containing 1% black carrot coated with 2% pectin, this value was determined as 47.24% for the sample that contained 0.5% black carrot extract, and as 64.86% for the sample that contained 0.25% black carrot extract. At the end of the 4-week storage period at +4°C, while 43.72% reduction was detected with ABTS method in the total antioxidant capacity of the encapsulated sample containing 1% black carrot in which 2% alginate was used as the coating material, this value was determined as 67.65% for the sample that contained 0.5% black carrot extract, and as 89.44% for the sample that contained 0.25% black carrot extract. Reduction in the total antioxidant capacity of the encapsulated samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 1% pectin-1% alginate coating material at the end of the 4-week storage period in +4°C was stated as 15.14%, 88.75%, 82.79% respectively with ABTS method. 0th week total anthocyanin amounts of the samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 2% pectin are 67.99±2.16, 42.91±1.07, and 23.57±1.16 mg cyn-3-gly/100g, respectively. At the end of the 4-week storage period at +4°C, while 36.14 reduction was detected in the total anthocyanin amount of the encapsulated product containing 1% black carrot coated with 2% pectin, this value was determined as 36.66% for the sample that contained 0.5% black carrot extract, and as 48.41% for the sample that contained 0.25% black carrot extract. 0th week total anthocyanin contents of the samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 2% alginate are 46.16±3.61, 24.34±1.42, 17.43±1.46 mg cyn-3-gly/100g, respectively. Again, at the end of the 4-week storage period in +4°C, while 60.69% reduction was detected in the anthocyanin amount of the encapsulated sample containing 1% black carrot in which 2% alginate was used as the coating material, this value was determined as 67.58% for the sample that contained 0.5% black carrot extract, and as 58.80% for the sample that contained 0.25% black carrot extract. 0th week total anthocyanin amounts of the samples containing %1, 0.5% and 0.25% black carrot encapsulated with 1% pectin-1% alginate are 70.32±1.28, 34.18±1.33, 15.81±1.53 mg cyn-3-gly/100g, respectively. The reduction in the amount of anthocyanins of the samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 1% pectin-1% alginate at the end of the 4-week storage period in +4°C, was stated as 8.29%, 78.09%, 68.05%, respectively. The average L* values expressed as luminous value at the beginning of the storage of the samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 2% pectin; of the samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 2% alginate and of the samples containing 1%, 0.5% and 0.25% black carrot encapsulated with 1% pectin-1% alginate were found as 2.86±0.04, 4.82±0.12, 7.80±0.11; 0.72±0.04, 1.64±0.06, 11.90±0.10; 6.58±0.10, 4.69±0.08, 4.11±0.02, respectively, and at the end of the storage period, the increase in the L* values are 79.65%, 82.30%, 67.30%; 94.67%, 92.74%, 55.36%; 38.74%, 78.57%, and 85.65%, respectively. The difference of the L* values at the end of the storage for all values is statistically important (P˂0.05). Throughout the examples, it was observed as the active ingredient concentration increased, the L* values decreased. Therefore, it indicates that the densest sample at the beginning of the storage is the capsule that contains 1% active ingredient encapsulated with 2% alginate with a value of 0.72±0.04. At the end of the storage, it was observed that a* and b* parameters were statistically important for the capsule samples containing active ingredients (P˂0.05). In the samples containing 0.5% and 0.25% active ingredient encapsulated with alginate and pectin-alginate, turning yellow was observed throughout the storage. In the light microscope study that was carried out, it was viewed with the light microscope that the capsules generated with 2% alginate had a more uniform and spherical structure. As a result of the analyses made, it was observed that the highest encapsulation efficiency, accordingly, the maximum protection was the capsule containing 2% pectin and 0.25% black carrot. At the end of the 4-week storage period in +4°C, while a reduction of respectively %51.87, 44.37%, and 58.75% was detected with CUPRAC method in the antioxidant capacity of the yoghurt samples enriched with encapsulated product containing 2% pectin and 1% black carrot extract, 1% pectin-1% alginate and 1% black carrot extract, the CUPRAC values of these samples at the beginning were measured as 152.24±20.21, 141.02±15.41, 160.87±24.90 mg TEAC/100 g, respectively. While spoiling was not observed in the yoghurts with capsule addition throughout the duration of the storage, spoiling was observed in the plain yoghurt in the 4th week, in the blueberry yogurt in the 3rd week, and in the yogurt colored with extract in the 4th week. The starting ABTS values of the yoghurt samples were measured as 13.20±9.32, 7.63±7.74, 13.75± 4.76, 6.69±5.75, and 17.28±3.15 mg TEAC/100g, respectively. At the end of the 4-week storage period at +4°C, while a reduction of 74.11% was detected with ABTS method in the antioxidant capacity of the yoghurt sample enriched with encapsulated product containing 2% pectin and 1% black carrot extract, this value could not be determined for the yoghurt sample enriched with encapsulated product containing 2% alginate and 1% black carrot extract and for the yoghurt sample enriched with encapsulated product containing 1% alginate – 1% pectine 1% black carrot extract as from the third week. Due to the fact that the yoghurt sample enriched with extract, yoghurt with blueberry and plain yoghurt samples displayed spoiling, a reduction could not be detected with ABTS method in the amount of antioxidant capacity throughout the storage period. The amounts of total anthocyanins of the yoghurt samples at the start of the storage were calculated as 313.61±20.30, 262.92±23.23, 234.84±16.58, 174.94±4.18, 318.55±16.71, and 149.50±7.61 mg cyn-3-gly/100 g, respectively. At the end of the 4-week storage period at +4°C, the reduction in the amounts of total anthocyanins of the yoghurt samples enriched with 2% pectin, 1% black carrot extract, 2% alginate, 1% black carrot extract, 2% alginate, and 1% black carrot extract was calculated as 50.70%, 38.04%, and 40.46%, respectively, and when the 0th and the last week were compared for these samples, the difference in the anthocyanin amount of the sample is statistically important (P˂0.05). Due to the fact that the yoghurt enriched with extract, yoghurt with blueberries and plain yoghurt displayed spoiling, a reduction in the anthocyanin amount could not be detected throughout the storage period. By examining the color values in the yoghurt samples, it was observed that the difference of the L* values between the start of the storage and the end of the storage was statistically significant (P˂0.05). The L* values increased compared to the start in all the samples, and the color became darker. In the yoghurt sample enriched with encapsulated product containing 2% pectin and 1% black carrot extract and 2% alginate - 1% black carrot extract, a statistically significant difference was not observed in the a* color values throughout the storage period. In the yoghurt colored with extract (a* value decreased), the statistical difference in the a* values of the yoghurt enriched with encapsulated product containing 1% alginate-1% pectin-1% black carrot extract and the plain yoghurt is meaningful (P˂0.05). In general, increase has been observed in the b* values of the samples, and the difference in the process of storage is statistically significant (P˂0.05). In plain yoghurt, however, b value has showed a decrease until the spoling process, and it is not statistically meaningful. Encapsulation of the black carrot extract rich in antioxidant with pectin, alginate and pectin-alginate complexes was carried out successfully, and an efficient encapsulation productivity has been attained. Throughout the storage period, the coating materials used in the encapsulation had the protective effect for the anthocyanins. Controlled release of the active substance is suitable for different applications in the food industry. Addition of the encapsulated black carrot to widely consumed yoghurt can be a good alternative in increasing its antioxidant content and to use instead of artificial colorants. With the addition of the encapsulated black carrot, consumers can consume more healthy products that contain natural antioxidants