Study on the Nutrient Components and Physicochemical Properties of Broccoli Flour

In order to promote the edible utilization of broccoli stalks and leaves, as well as solve environmental issues from broccoli residues, the whole broccoli was chosen as materials and divided into florets, stalks and leaves to analyze the nutrients and minerals contents, thermal stability and the morphology of freeze-dried broccoli flours. The chromaticity, density, swelling capacity, water-holding and oil-holding capacities of broccoli florets, stalks and leaves were also measured. The results showed that the content of flavone in broccoli leaves was 19.82±0.86 mg/g, chlorophyll of 11.35±0.65 mg/g, calcium of 11.27±0.48 mg/g, copper of 20.23±0.81 μg/g, manganese of 29.62±0.71 μg/g, which were all higher than those in stalks and florets significantly (P<0.05). There were differences in particle size and specific surface area among samples at the same mesh, in which broccoli stalks had the highest size and lowest specific surface area. The compressibility of three samples increased with decreasing in particle size. The broccoli leaves and stalks had higher compressibility under 180-mesh than florets. However, the compressibility of leaves at 180-mesh was different from stalks insignificantly (P>0.05). The leaves and florets had high swelling capacity, but stalks and florets had high water-holding and oil-holding capacities. The florets had the highest water-holding and oil-holding capacities among three samples at 140-mesh, which were 13.18±0.46 g/g and 1.77±0.13 g/g, respectively. With consideration of processing costs, 140-mesh was the optimum size for florets, stalks and leaves of broccoli flours.