Abstract: A fermented beverage and a preparation method are disclosed. The method uses ripened fruits and/or vegetables as raw materials. The method includes performing a natural ripening on a fruit and/or a vegetable at 15° C. to 30° C. for 5 days to 10 days to obtain a ripened fruit and/or vegetable; and inoculating lactic acid bacteria into the ripened fruit and/or vegetable, and performing a fermentation for 10 days to 30 days at 15° C. to 30° C. to obtain the fermented beverage. After 23 days of fermentation, the fermented beverage has a total flavonoid content up to 0.5 mg/mL to 2.0 mg/mL, which is beneficial to human health, a pH of 3.2 to 3.8 and a total titratable acidity of up to 12 mg/mL to 18 mg/mL. The fermented beverage requires a short fermentation cycle, which is beneficial to industrial production.

Abstract: The invention provides a method for establishing a separable regeneration system for verifying regeneration effect between two antioxidants, which belongs to the field of regeneration effect of antioxidants. According to different solubilities of two antioxidants, lipid-soluble antioxidant is first combined into PE film, and water-soluble antioxidant is dissolved into deionized water and a separable regeneration system where antioxidants can contact with other but not dissolve in each other is formed. This method compares the differences of change of antioxidant capacity in aqueous phase with and without lipid-soluble antioxidant so that to judge whether the added lipid-soluble antioxidant has regeneration effect on aqueous-soluble antioxidant. The present invention effectively verifies the regeneration effect between different antioxidants, and has advantages of simple operation, less interference factors, intuitive and high efficiency.

Abstract: Disclosed is a method for non-destructive detection of egg freshness based on Raman spectroscopy technology, which belongs to the field of food detection. Partial least squares regression models are built using Raman spectroscopic data and measured values of physicochemical indexes for egg freshness, which can be used to predict egg freshness based on Raman spectrum of egg shell surface. The Raman spectroscopic data are collected in the waveband of 100-3000 cm?1. The physicochemical indexes used in the invention include the Haugh unit, the albumen pH, the air chamber diameter and the air chamber height. By using the partial least squares model, values of physicochemical index for egg freshness can be obtained from Raman spectra collected on egg shell surfaces, thus achieving the goal of non-destructive detection of egg freshness.

Abstract: The invention provides a method for establishing a separable regeneration system for verifying regeneration effect between two antioxidants, which belongs to the field of regeneration effect of antioxidants. According to different solubilities of two antioxidants, lipid-soluble antioxidant is first combined into PE film, and water-soluble antioxidant is dissolved into deionized water and a separable regeneration system where antioxidants can contact with other but not dissolve in each other is formed. This method compares the differences of change of antioxidant capacity in aqueous phase with and without lipid-soluble antioxidant so that to judge whether the added lipid-soluble antioxidant has regeneration effect on aqueous-soluble antioxidant. The present invention effectively verifies the regeneration effect between different antioxidants, and has advantages of simple operation, less interference factors, intuitive and high efficiency.

Abstract: The present invention discloses a molecularly imprinted fluorescence sensor based on carbon dots for detecting chloramphenicol (CAP) and its preparation method and its application. This invention uses carbon dots (CD) as fluorescence carrier and molecularly imprinted membrane (MIP) as enrichment container to synthesize fluorescent molecularly imprinted material with core-shell structure so that to achieve a rapid and specific detection of CAP. The reverse micro-emulsion method was used, firstly a reverse microemulsion system was established, CAP was used as a template molecule in the water phase, and a molecularly imprinted membrane was synthesized on the surface by using CD as a carrier. The prepared material is nano-sized microspheres with excellent water-dispersibility and stability. It has good sensitivity to the target substance CAP, rapid detection speed, strong specific selectivity, strong chemical stability and low cost, and has good application prospects in the detection of CAP.

Abstract: A method for rapidly detecting S. typhimurium in milk through a Raman spectrum based on heavy water marking. The method comprises the steps of adding to-be-detected milk possibly containing S. typhimurium into culture media containing heavy water for culturing, then collecting cultured S. typhimurium cells and conducting Raman spectrum scanning, and analyzing and processing an obtained original Raman spectrum, so that S. typhimurium in the to-be-detected milk is detected. According to the method of the invention, D2O marking is adopted, and the Raman spectrum is used for rapidly detecting S. typhimurium in milk, so that the method has the advantages of being short in detection time (4-8 h), high in sensitivity, low in cost, easy to operate, convenient and fast to implement and the like; the detection limit is 104-108 cfu/mL, interference from the matrix in a milk sample is small, and the method is an ideal method for rapidly detecting S.

Abstract: A method for representing the quality change process of beef fat during repeated freezing and thawing through a Raman spectrum. The method comprises the steps of (1) setting operating parameters of a laser Raman spectrometer, wherein the operating parameters include the wavelength of exciting light, the laser power and the scanning time; (2) repeatedly freezing and thawing beef, extracting fat in the thawed beef, and then conducting Raman spectrum scanning on the extracted fat; (3) analyzing and processing an obtained original Raman spectrum, so that the quality change process of beef fat during repeated freezing and thawing is represented. The Raman spectrum is used for monitoring the quality change process of beef fat during repeated freezing and thawing, the method is flexible and simple, the analysis speed is high, and the fat quality of beef which is repeatedly frozen and thawed can be represented efficiently and accurately; in addition, analysis solvent consumption is low, and the detection cost is low.

Abstract: A detection method of bisphenol A by the surface-enhanced Raman spectroscopy includes: soaking and extracting bisphenol A present in a sample with an organic solvent to form an extraction solution, adding methanol to the extraction solution to cause a polymer to precipitate from the extraction solution and leaving a filtrate behind, filtering and concentrating the filtrate, diluting the concentrated filtrate to volume with methanol, filtering the diluted filtrate through a filter with a pore size of 0.45 ?m to obtain a pretreated sample; detecting bisphenol A present in the sample by Raman spectroscopy under an incident laser power of 100 to 300 mW, and a scan time of 2 to 20 seconds; mixing the pretreated sample with the colloidal gold in an appropriate ratio, followed by adjusting pH value, and then carrying out the detection of bisphenol A present in the sample by Raman spectroscopy.

Abstract: A detection method of bisphenol A by the surface-enhanced Raman spectroscopy includes: soaking and extracting bisphenol A present in a sample with an organic solvent to form an extraction solution, adding methanol to the extraction solution to cause a polymer to precipitate from the extraction solution and leaving a filtrate behind, filtering and concentrating the filtrate, diluting the concentrated filtrate to volume with methanol, filtering the diluted filtrate through a filter with a pore size of 0.45 ?m to obtain a pretreated sample; detecting bisphenol A present in the sample by Raman spectroscopy under an incident laser power of 100 to 300 mW, and a scan time of 2 to 20 seconds; mixing the pretreated sample with the colloidal gold in an appropriate ratio, followed by adjusting pH value, and then carrying out the detection of bisphenol A present in the sample by Raman spectroscopy.