The black millet has been favored because of its unique color, rich in nutrients and beneficial to human health. The differences between components of black millet and yellow millet were analyzed in this work. Besides, the rheological characteristics of black and yellow millet were measured by Mixolab in order to evaluate the functional properties of protein and starch in millet. The product of millet crust were also prepared by three different processing techniques. The results showed that the black millet has a higher nutritional value than the ordinary yellow millet, especially in protein, oil and mineral salts content. The results of Mixolab showed that the black millet had a relative good protein stability, starch thermostability and processing characteristics. Our work will supply scientific evidences and technical supports in application of black millet and its products in future.
In order to investigate the effect of different extracting juice technologies on quality and antioxidant activity of sweet potato juice, four pretreatment methods were selected.The light transmittance, color, sensory quality and main nutritional ingredient(protein,Vc,β-carotene,toal phenolics,flavonoids) were compared and analyzed. The antioxidant activity of sweet potato juice was evaluted by means of five vitro antioxidant systems(DPPH,ABTS+,·OH,·O2-radical scavenging and total reducing force mathod).The results showed that The retention rate of sweet potato juice and the main components after atmospheric cooking were slightly inferior to microwave cooking, but its color and stability were better. The nutrient loss of sweet potato juice was the highest after the high pressure cooking, and the loss rate of vitamin C and β-carotene was Up to 92.54% and 72.25%, and the browning is serious.Moreover, after screw extrusion,the nutrient retention rate of sweet potato juice was the highest, and the storage rate of soluble protein was 94.55%, the antioxidant activity was high and the comprehensive quality was good.
In recent years, Chinese Maca industry has been through a roller coaster development, along with the price skyrocketed and plummeted. When Maca held at high price, the phenomenon adding the inferior powder (corn flour, radish powder and turnip powder etc.) into commercial Maca powder was overwhelmingly universal. In the present study, the microstructures of corn flour, radish powder, turnip powder and Maca powder were investigated by desktop scanning electron microscopy (SEM), and elemental compositions of turnip and Maca powder were analyzed. The result illustrated that radish powder and corn flour were evidently different from the micro-morphology of Maca powder. Turnip powder was the closest to Maca powder, but there were still apparent
differences. By X-ray energy spectrum analysis, the result showed: if N and O element mass ratio were close to 43.75% ± 0.79% and 29.92% ± 0.74% respectively, the sample was considered pure Maca powder preliminarily; otherwise the measured was suspected to fake Maca powder .Meanwhile, electronic nose was used to detectedMaca powder adding different proportions turnip powder. It was suggested that the fingerprints of Maca powder with distinct degree adulteration appeared a certain regularity. Electronic nose not only could effectively identify the authenticity of Maca powder, but might also roughly determine the proportional range of adulteration. Additionally, quality control of raw materials and products could be attained by statistical quality control (SQC) analysis model.Fresh tea leaves plunked from Chibiquntizhong in Chibi tea area were taken as raw materials to make Qingzhuan tea. Volatile components of Qingzhuan tea during the primary and pile fermentation process were analyzed using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The result showed that 62 volatile compounds were identified from Qingzhuan tea samples, while 45, 41, 41, 40, 43, 42 and 48 compounds were identified from fresh leaves to the end of pile fermentation 7 samples in total. In theprevious stage of pile fermentation, aldehydes, alcohols, ethers and ketones had a relatively higher content. However, the relative amount of olefin aldehydes, ketones, methoxybenzene and furans significantly increased, alcohols and ethers obviously decreased which caused by microbial action during pile fermentation. Twelve high OAV (>1) ofβ-ionone, linalool, (Z)-4-heptenal, (E,Z)-2,6-nonadienal, decanal, (E)-2-nonenal, (E,E)-2,4-heptadienal, 1-octen-3-ol, nonanal,α-ionone, 1-penten-3-one and 2-octen-1-al indicated their importance to the aroma character of Qingzhuan tea in the different process stages. Pile fermentation was the key step in the formation of volatile flavor compounds in Qingzhuan tea. The characteristic aroma components of Qingzhuan raw tea were include (E,E)-2,4-heptadienal, 2-octen-1-al, (E,Z)-2,6-nonadienal, nonanal, benzeneacetaldehyde,β-cyclocitral，β-ionone,α-ionone, 1,2,3-trimethoxybenzene andα-terpineol, et
