Formation of Amadori compounds in LIGAO (concentrated pear juice) processing and the effects of Fru-Asp on cough relief and lung moisturization in mice

Identification of Volatile Organic Compounds and Analysis of Aroma Characteristics in Ten Pear Syrups

Aroma in food plays an important role in food perception and acceptance, which depends on various mixtures of volatile organic compounds (VOCs). Moreover, VOCs are of great significance for aroma identification. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) technology was used to determine the VOCs in 10 pear syrups. A total of 127 VOCs were quantitatively determined, including 9 common VOCs and 46 characteristic VOCs of 10 pear syrups. The pear syrups were divided into three categories by cluster analysis, and thirty-eight differential VOCs were obtained using orthogonal partial least squares discrimination analysis (OPLS-DA) and fourteen key VOCs were selected by odor activity value (OAV). It was revealed that the key and common aroma components of pear syrups were butanoic acid, methyl ester, 2-methyl-, methyl ester and Hexanoic acid, and ethyl ester. The characteristic and differential VOCs were 10-Undecen-1-ol, Hexadecanal, n-Propylacetate, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1S,2R,5S)-, Methional, Disulfide, dimethyl, 8-Nonenoic acid, ethyl ester, Naphthalene, 1,2-dihydro-1,1,6-trimethyl-, 3H-Purin-6-amine, N,N,3-trimethyl-, 2-Octanol,2,6-dimethyl-, Furyl hydroxymethyl ketone, Heptane, 2,2,4,6,6-pentamethyl-, and Butanoic acid,2-methyl-,methyl ester. The above results showed that different pear syrups had rich diversity in aroma compounds, with some components being shared among them while others are exclusive to specific syrups.

Aqueous preparation of arginyl-fructosyl-glucose (a maltose-arginine AC) and determination of Amadori compounds (ACs) in red ginseng by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS)

Amadori compounds (ACs) are key Maillard intermediates in various foods after thermal processing, and are also important non-saponin components in red ginseng. Currently, due to the difficulty in obtaining AC standards, the determination of multiple ACs is limited and far from optimal. In this study, an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. A green synthetic method was developed for arginyl-fructosyl-glucose (AFG), the major AC in red ginseng with potential health benefits. The UPLC-MS/MS method was then applied in identification and quantification of ACs in red ginseng samples, which showed for the first time that 12 other ACs also exist in red ginseng in addition to AFG and arginyl-fructose (total 98.88 % of all ACs). Contents of AFG and arginyl-fructose in whole red ginseng were 36.23 and 10.80 mg/g dry weight, respectively. Raw ginseng can be steamed and then dried whole to obtain whole red ginseng, or sliced before drying to obtain sliced red ginseng. Slicing before drying was found to reduce ACs content. Results of the present study will help to reveal the biological functions of red ginseng and related products associated with ACs and promote the standardization of red ginseng manufacture.

Preparation of red jujube powder with high content of Amadori compounds and higher antioxidant activity by controlling the Maillard reaction

Amadori compounds (ACs) are stable compounds produced in the early stage of the Maillard reaction (MR) with health benefits such as immunomodulatory, antithrombosis, and tumor-preventive effects. Jujube is a medicinal and edible fruit in China. It is rich in free amino acids and reducing sugar, but traditionally, little attention was paid to the formation of ACs when jujube was processed, neither the influence of ACs on health effects. In this paper, we aimed to increase ACs through controlling the MR during different heating processes of jujube powder with adjusted water content and find the most effective AC that contributed to the antioxidant effects of jujube powder. The optimal dry-heating conditions to produce ACs were as follows: The water activity was 0.294, the heating temperature was 90°C, and the time was 120 min. After processing, the ACs content of jujube powder was 18.55 ± 0.19 mg/g dry weight (DW), which was more than 100 times of those in the unheated jujube powder (0.153 ± 0.003 mg/g DW). Besides, the antioxidant activity of jujube powder after dry-heating process was higher than that of unheated one. As the most abundant AC in the dry-heated jujube powder (12.90 ± 0.75 mg/g DW), N-(1-deoxy-d-fructose-1-yl) proline (Fru-Pro) showed the highest antioxidant activity (62% of equivalent l-ascorbic acid) among 12 ACs in ferric reducing antioxidant power assay. This result provided a method to produce jujube product with high content of ACs and confirmed the positive contribution of Fru-Pro to the antioxidant activity of the jujube powder.