Development of flavour and aroma rich garlic powders using different drying approaches

Garlic (Allium sativum L.) is widely consumed around the world in various forms, such as fresh, canned purée, garlic oil and powder, as a flavouring and aromatising agent in food and as a herbal medicine, due to its rich aroma and bioactive components. The powdered form, obtained by drying garlic, is particularly important as it is a long-lasting, value-added product that can be added directly to meals, as well as to powdered food formulations and spice mixtures. This study tested the PKD-KPK method, which uses a pyrometer to control infrared-assisted diffraction window drying, for the qualified production of garlic powder. The industrial use of garlic powder has become widespread, and consumer demand has increased. Different drying methods commonly applied in the industry were tested comparatively. This technology was used for the first time in the production of garlic powder. To produce garlic powder that is rich in bioactive components and has a strong aroma, the drying conditions for pureed garlic in the PKD-KPK system were first optimised under controlled conditions. Under the optimum drying conditions obtained, drying was carried out by adding suitable carriers to the mash, and the carrier composition added for this process was optimised. Additionally, to determine the most effective drying approach, foam drying was conducted under optimal conditions, and the application parameters of this process were also refined. To produce garlic powder rich in aroma and bioactive components, the effectiveness of the PKD-KPK system was evaluated in detail, and different drying methods were systematically compared. In the first stage of the study, garlic purée was dried under optimised conditions in the PKD-KPK system. The optimum drying conditions were determined as a result of the Box-Behnken optimisation study: an air flow rate of 0.9 m/s, a drying water temperature of 60 °C and a mash surface temperature of 30 °C. The drying time was recorded as 50 minutes under these conditions. In the second stage, the carrier composition was optimised using the I-Optimal experimental design, determining the optimal carrier ratios as 1.841 g of gum arabic and 3.159 g of maltodextrin. Under these conditions, the drying time decreased to 33.6 minutes. In the next stage, foam drying was attempted to increase the drying speed and improve product quality. In this process, the optimum utilisation rate of the extract selected as the foaming agent was determined to be 0.33%, the foaming time was determined to be 2.25 minutes and the final moisture content was reached after 28 minutes of drying the foamed garlic puree in the PKD-KPK system. Following the optimisation studies, the powdered products obtained using different drying methods (PKD-KPK, oven drying and freeze drying) and from various forms of garlic (purée, cloves and slices) were evaluated in terms of their sensory, physical and chemical quality parameters, as well as their storage properties. In terms of physical properties, the lowest browning index value of 6.56 ± 0.02 was observed in the freeze-dried purée form. Conversely, the oven-dried mash sample exhibited the highest browning index value of 24.31 ± 0.29. In particle size analysis, the lowest D4,3 value of 8.39 ± 0.25 was determined in the freeze-dried mash sample, while this value increased to 17.27 ± 1.29 in the sample dried using a carrier in the PKD-KPK system. According to the chemical analysis results, the total phenolic content (TPC) was best preserved in the foam-dried sample in the PKD-KPK system, at 3.31 ± 0.01 mg GAE/100 g KM. The highest loss was determined in the oven-dried purée sample, at 1.71 mg GAE/100 g KM. Antioxidant activity was found to be 21.93 ± 0.11 g TEAA/kg KM for samples dried using the PKD-KPK system, whereas freeze-dried samples exhibited an average range of 18.26–11.64 g TEAA/kg KM. In terms of allicin content, the protective effect of the PKD-KPK system was significant. While the allicin content of samples dried using this system ranged from 6.72 to 4.60 mg/kg KM, oven-dried samples were found to have a much lower value in the range of 1.40 to 0.10 mg/kg KM. The sample dried by adding a carrier in the PKD-KPK system preserved the highest level of total aroma (peak area of 4.10E+08 ± 1.96E+05), while the sample dried by freeze-drying in slice form experienced the highest aroma loss (peak area of 2.72E+08 ± 4.02E+05). In the sensory analysis, samples dried with and without a carrier in the PKD-KPK system generally received high scores (4.6 and 4.3) from the panelists. During the storage period, the monitored parameters showed a decreasing trend in all samples after 90 days. However, losses were minimal in samples dried using the PKD-KPK system. For instance, the allicin content of the sample with a carrier was 6.33 mg/kg KM on day 0; this decreased to 4.81 mg/kg KM after 90 days, representing a loss of 24%. The TPC value fell from 2.81 to 2.37 mg GAE/100 g KM, and the antioxidant activity decreased from 13.47 to 11.64 g TEAA/kg KM during this period. In the oven-dried slice sample, over 50% of the allicin content was lost, decreasing to 0.67 mg/kg KM. Contrary to the changes in other parameters, aroma values increased in all samples. Freeze-dried samples showed an increase in aroma of over 50%, whereas the increase was between 14% and 16% in samples dried using the PKD-KPK system. In conclusion, the PKD-KPK drying system demonstrated superior performance in terms of product quality, as well as the stability of bioactive and aromatic components. Its advantages in terms of energy efficiency, product quality, and shelf-life parameters suggest that it may be a highly preferable alternative for industrial applications.