Drying Kinetics, Grinding Characteristics, and Physicochemical Properties of Broccoli Sprouts

Abstract

In this study, we studied the drying process, grinding characteristics and physicochemical characteristics of broccoli sprouts (BS). The seeds of broccoli were germinated at 20 °C for 3 and 6 days. Then, the seeds were air- and freeze-dried, and the Page model was used for prediction of drying kinetics of broccoli sprouts. It was observed that the drying time of BS decreased about twofold as the air-drying temperature increased from 40 to 80 °C. An increasing the air-drying temperature from 40 to 80 °C decreased the drying time by approximately twofold. Freeze-drying of sprouts took the longest drying time. Germination of seeds significantly decreased the value of grinding energy requirements, and the ground sprouts exhibited a different grinding pattern in comparison to ground non-germinated seeds. In terms of color parameters, the highest lightness and yellowness were found for freeze-dried sprouts. Redness and yellowness of sprouts increased with an increase in the air-drying temperature. The lowest total color difference was obtained for the freeze-dried sprouts. Higher drying temperature resulted in lower total phenolics content (TPC) and decreased antioxidant activity (AA). The highest TPC and AA were observed in air-dried sprouts (40 °C) and freeze-dried sprouts after 6 days of germination.

Investigating the Influence of Infrared Drying Method on Linden (Tilia platyphyllos Scop.) Leaves: Kinetics, Color, Projected Area, Modeling, Total Phenolic, and Flavonoid Content

“…According to Diziki, D., et al [ 28 ], total color difference (∆E) was determined as follows: ∆E = [(L − L o ) 2 + (a − a o ) 2 + (b − b o ) 2 ] 1/2 where L o , a o and b o indicate the brightness, redness, and yellowness of dried samples, respectively.…”

Sprouts and Microgreens: Trends, Opportunities, and Horizons for Novel Research

“…Conditions and methods of sprouts drying should be chosen based on whether quality can be preserved or enhanced. For example, in broccoli sprouts the highest efficiency of grinding as well as the higher total phenolic content and antioxidant activity were obtained from freeze-dried (frozen and lyophilized at 40 • C; 52 Pa) materials, although air-dried at 40 • C (air flowing, 0.5 ms −1 ) could be also recommended [172]. In alfalfa and flax sprouts, freeze-drying minimized the chemical alteration of the product, resulting in a better preservation of antioxidants and an increase in phytosterol availability [173].…”

Enhancing Wheat Sprout Attributes Using “Intensification of Vaporization by Decompression to the Vacuum”, an Innovative Drying–Texturizing Technology

“…Certain studies have drawn comparisons between solar and hot-air drying, focusing on nutritional parameters such as folate content or antioxidant activity [21,22]. Several studies have investigated various temperatures in hot-air drying processes [23], while only a few have compared these to freeze drying [24][25][26].…”

“…The prevailing consensus emerging from these research findings suggests that mild hot-air drying, conducted at temperatures ranging from 40 to 60 • C, is the recommended choice for preserving sprouts [24,27]. Nonetheless, a low drying temperature results in a prolonged air-drying duration.…”

“…To tackle this issue, researchers have investigated the impact of grinding on the drying kinetics of sprouts, demonstrating that this pretreatment method effectively shortens the drying duration [24]. Yet this destructive technique is solely feasible when the desired end product is in the form of powder or small flakes.…”