Abstract: A system and method are disclosed for identifying a media item to be provided to a group of users of a content sharing platform, wherein the media item is associated with a category, and wherein each user in the group of users is associated with a weight indicating a probability of a correspondence between a respective user and the category associated with the media item, receiving a request to change a size of the group of users from a first level to a second level, the first level corresponding to a first weight threshold for the group of users, and calculating, based a value indicating a difference between the first level and the second level, a second weight threshold for the group of users corresponding to the second level, the second weight threshold to be subsequently used to determine whether the media item is to be provided to a user requesting content from the content sharing platform.

Abstract: The present invention relates to an enzyme combination, genetically engineered bacteria, and application thereof in producing D-psicose. Glucose isomerase and D-psicose 3-epimerase from specific sources are separately co-expressed in Bacillus subtilis, a combination enzyme containing glucose isomerase and D-psicose 3-epimerase is obtained through fermentation, and the combination enzyme is used to catalyze a glucose substrate to perform isomerization to eventually prepare D-psicose. The method provided in the present invention can clearly increase a conversion rate of D-psicose, which greatly reduces the time of converting glucose into D-psicose. In addition, inexpensive glucose is used as a raw material, so that the production costs of D-psicose are greatly reduced. In the present invention, fructose syrup may be synchronously produced, so that the input for a whole set of production lines of fructose syrup is omitted, thereby greatly improving the economic benefits.

Abstract: The present invention relates to an enzyme combination, genetically engineered bacteria, and application thereof in producing D-psicose. In the present invention, glucose isomerase and D-psicose 3-epimerase from specific sources are co-expressed in Bacillus subtilis. A crude enzyme preparation is obtained by fermenting obtained engineered bacteria, and isomerization is performed by using high-concentration glucose as a substrate. Fructose syrup and D-psicose syrup are obtained by performing isolation, purification, and concentration. The enzyme combination provided in the present invention has a high catalytic rate for a substrate, and can clearly increase a conversion rate of D-psicose. In addition, inexpensive glucose is used as a raw material, so that the production costs of D-psicose are greatly reduced.

Abstract: The technology is generally directed to personalizing digital components for users based on a merged preference profile. The merged preference profile may be generated based on declared and inferred preferences of the users. The declared and inferred preferences may be preferences related to brands, topics, types of products, etc. The merged preference profile may be used to personalize the digital components output to the user. For example, when identifying digital components to be selected, at least some of the digital components may be selected based on the merged preference profile of the user. At least a portion of the selected digital components may be digital components with a subject matching the preferences of the user, thereby improving the digital components output to the user.

Abstract: The invention discloses a gardenia blue pigment with high brightness and low redness and a preparation method therefor, and belongs to the technical field of pigment extraction. Genipin, an enzymolysis product of gardenia extract, is used as a raw material. Genipin and amino acids (phenylalanine, tryptophan, glycine, or tyrosine) are weighed at a molar ratio of 1:(0.375-0.75), and subjected to a polymerization reaction under a conventional condition to generate a gardenia blue precursor. The gardenia blue precursor is oxidized to develop a color, refined by using ultrafiltration membrane, and finally spray-dried to obtain the gardenia blue pigment with high brightness, low redness, and low cost.

Abstract: A method for preparing beta-carotene from pepper pigment includes: (1) enzymatic hydrolysis of paprika oleoresin to obtain a paprika red pigment hydrolysate; (2) extraction of the paprika red pigment hydrolysate to obtain a paprika red pigment solution; (3) refined filtration to obtain a paprika red pigment filtrate; (4) adsorption: carrying out chromatographic separation with a medium-pressure silica gel chromatographic column, and collecting an effluent from the chromatographic column; (5) elution of beta-carotene; (6) elution of yellow pigments; (7) elution of red pigments; and (8) elution of orange pigments. The invention combines enzymatic hydrolysis with medium-pressure column chromatography for the first time, where chromatographic silica gel with smaller particle size is used for adsorption, and four-stage elution treatment is carried out, so that beta-carotene with a content of more than 20% can be directly separated, and at the same time, reddish paprika red pigment with higher quality is prepared.

Abstract: A method for preserving a fermentation broth of an engineered strain of D-psicose-3-epimerase includes: adding a lysozyme into a fermentation broth of an engineered strain of D-psicose-3-epimerase, stirring to make the OD600 of the fermentation broth less than or equal to 1 to obtain an enzyme solution; and adjusting the enzyme solution to be weakly alkaline with an alkali liquor, and storing the weakly alkaline enzyme solution at room temperature. According to the invention, the enzyme solution is obtained by adding the lysozyme after fermentation, and then adjusted to be weakly alkaline. The lysozyme can dissolve the engineered strain to release the enzyme, and can also inhibit the growth of microorganisms. The alkaline environment of the enzyme solution can further inhibit the growth of other microorganisms in the enzyme solution. Therefore, the storage life of the enzyme solution is prolonged while ensuring the enzyme activity.

Abstract: A method of preparing paprika red pigment with low polycyclic aromatic hydrocarbons includes (1) drying, crushing and granulating mature peppers to obtain pepper particles; (2) extracting the pepper particles with a vegetable oil in a rotocel extractor to obtain a paprika red pigment solution; (3) extracting the paprika red pigment solution with an ethanol solution in a liquid-liquid extractor to remove spicy substances; (4) running the paprika red pigment solution through a low-pressure chromatography column to remove polycyclic aromatic hydrocarbons; and (5) concentrating the paprika red pigment solution to obtain the paprika red pigment with low polycyclic aromatic hydrocarbons.

Abstract: The invention discloses a gardenia blue pigment with high brightness and low redness and a preparation method therefor, and belongs to the technical field of pigment extraction. Genipin, an enzymolysis product of gardenia extract, is used as a raw material. Genipin and amino acids (phenylalanine, tryptophan, glycine, or tyrosine) are weighed at a molar ratio of 1:(0.375-0.75), and subjected to a polymerization reaction under a conventional condition to generate a gardenia blue precursor. The gardenia blue precursor is oxidized to develop a color, refined by using ultrafiltration membrane, and finally spray-dried to obtain the gardenia blue pigment with high brightness, low redness, and low cost.

Abstract: A system and method are disclosed for identifying a media item to be provided to a group of users of a content sharing platform, wherein the media item is associated with a category, and wherein each user in the group of users is associated with a weight indicating a probability of a correspondence between a respective user and the category associated with the media item, receiving a request to change a size of the group of users from a first level to a second level, the first level corresponding to a first weight threshold for the group of users, and calculating, based a value indicating a difference between the first level and the second level, a second weight threshold for the group of users corresponding to the second level, the second weight threshold to be subsequently used to determine whether the media item is to be provided to a user requesting content from the content sharing platform.

Abstract: A method of preparing paprika red pigment with low polycyclic aromatic hydrocarbons includes (1) drying, crushing and granulating mature peppers to obtain pepper particles; (2) extracting the pepper particles with a vegetable oil in a rotocel extractor to obtain a paprika red pigment solution; (3) extracting the paprika red pigment solution with an ethanol solution in a liquid-liquid extractor to remove spicy substances; (4) running the paprika red pigment solution through a low-pressure chromatography column to remove polycyclic aromatic hydrocarbons; and (5) concentrating the paprika red pigment solution to obtain the paprika red pigment with low polycyclic aromatic hydrocarbons.

Abstract: The invention relates to a method for the determination of crocetin and its derivative amounts and the derivative composition from gardenia yellow. The method mainly comprises of following steps: the absorbance measurement of a gardenia yellow aqueous solution at known concentration by UV-VIS, the absorption coefficient measurement of total crocetin derivative, the total crocetin derivative amount calculation according to Lambert-Beer law, the relative amount calculation of each crocetin derivative from its absorption coefficient and peak area on HPLC, the amount calculation of each crocetin derivative from the total amount of crocetin derivative and the relative amount of each crocetin derivative, and finally total crocetin amount calculation.

Abstract: The invention relates to a method for the determination of crocetin and its derivative amounts and the derivative composition from gardenia yellow. The method mainly comprises of following steps: the absorbance measurement of a gardenia yellow aqueous solution at known concentration by UV-VIS, the absorption coefficient measurement of total crocetin derivative, the total crocetin derivative amount calculation according to Lambert-Beer law, the relative amount calculation of each crocetin derivative from its absorption coefficient and peak area on HPLC, the amount calculation of each crocetin derivative from the total amount of crocetin derivative and the relative amount of each crocetin derivative, and finally total crocetin amount calculation.