The study was aimed to explore the changes of basic nutrients, active substances and antioxidant activity of the Macadamia flowers in the bud swelling period, early flowering, and full-flowering stages, and provide the basis for its development and utilization. The changes of basic nutrients, active substance content and antioxidant activity of the Macadamia flowers at the bud swelling period, early flowering stage and full-flowering stage were systematically analyzed. The results showed that among the basic nutrients of the Macadamia flowers at three flowering stages, the water content showed a decreasing trend [the highest at the bud swelling period was (70.99±2.58)%]. Soluble protein was the highest (0.054±0.009)% in the bud swelling period. Crude fat increased first and then decreased [the highest was (2.20±0.021)% at early flowering]. The total ash content decreased first and then increased [the highest was (3.73±0.02)% at full-flowering stage]. The early flowering stage of total sugar was the highest (1.65±0.19)%. It contained 16 abundant amino acids (7 essential amino acids and 9 non-essential amino acids), and the total amino acid content decreased with the development of flowering period. The proportion of essential amino acids and E/N value were close to the international high-quality protein standard, showing good protein nutritional value. In the Macadamia flowers at different flowering stages, the contents of five major elements in the three flowering stages showed the order of K>Ca>P>Mg>Na, highlighting the advantages of high K and low Na. The content of K at full-flowering stage was 5.2 times that of banana, and the content of Ca was 5.0 times that of milk. However, as a food development, it is necessary to pay attention to the risk of excessive As, Cr and other harmful elements. A total of 22 (the bud swelling period), 14 (early flowering stage) and 20 (full-flowering stage) volatile components were identified, mainly hexanal and d-limonene, which together constituted its unique floral characteristics. The analysis of active components showed that the content of total polyphenols decreased significantly with the prolongation of flowering period, and the bud swelling period was (18.47±2.3)mg/g. The content of total flavonoids increased first and then decreased, and the content was the highest in the early flowering stage, reaching (8.09±0.63)mg/g. The antioxidant activity evaluation showed that the DPPH and ABTS free radical scavenging rates were the highest in the bud swelling period, which were (89.96±0.61)% and (99.50±0.22)%, respectively, and the antioxidant capacity was strong. In summary, the Macadamia flowers are rich in amino acids, minerals and active substances from the bud swelling period to the full-flowering stage, and have high antioxidant capacity, which provides a scientific basis for their subsequent development and utilization.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |