Utilization of Maillard reaction in moist-dry-heating system to enhance physicochemical and antioxidative properties of dried whole longan fruit

Abstract

This research aimed to enhance the physicochemical and antioxidant properties of dried whole longan fruit using Maillard reaction or non-enzymatic glycosylation (glycation) in a moist-dry-heating system at 60 C with approximately 75% relative humidity for 5-50 days. During Maillard reaction, the browning index (BI) of the fruits increased significantly while lightless, redness and yellowness decreased. Interestingly, the rare sugars especially D-psicose and D-allose gradually increased by 2-3 folds when compared to the initial Maillard reaction. The development of D-mannose was additionally established through the glycation. The degree of glycation increased with the decrease of free amino acid, suggesting that conjugation of sugar with amino acids was involved. SDS-PAGE confirmed that the high molecular weight (HMW) of conjugated sugar-amino acid was the Maillard reaction product. The antioxidative properties including DPPH and ABTS radical scavenging activities, also ferric reducing antioxidant power (FRAP) were also increased as Maillard reaction progressed, which showed the activities in the range of 43.2-94.1 mg GAE/100 g dry basis, 0.23-3.09 g TE/100 g dry basis, and 0.35-5.95 g FeSO 4 /100 g dry basis, respectively. This study demonstrated a practical approach of Maillard reaction for the development of dried longan fruit with high antioxidative properties.

Extraction, purification, structural features and biological activities of longan fruit pulp (Longyan) polysaccharides: A review

“…The structural features of LPs-protein complexes can be monitored by measuring their free amino content, ultraviolet-visible spectrum (UV-Vis), FT-IR and Mw distribution to determine whether a MR occurs between LPs and proteins ( 71 ). Furthermore, In vitro activity evaluation showed that dry-heat-induced MR effectively enhances the anti-oxidant, anti-tumor and immune-stimulating activities of LPs ( 72 ). Meanwhile, the LPs-protein polymers formed by MR usually exhibit better properties, such as emulsification, thermal stability and solubility, than pure proteins or simple mixtures of protein-LPs.…”

Dry but Not Humid Thermal Processing of Aloe vera Gel Promotes Cytotoxicity on Human Intestinal Cells HT-29

“…Applying heat during the drying procedure can be associated to several effects: First, polysaccharides and proteins may covalently bond via Maillard reactions, especially under hot and dry conditions, and can easily be seen as an increased browning of the final product, which will have altered biological activities [ 33 ]. Applying humid (PAG) instead of dry (DAG) heat reduces Maillard reactions, as evidenced by less browning of the final product [ 13 , 34 ], and a two- to three-fold reduction of cytotoxicity to the HT-29 human intestinal cell line ( Table 1 ).…”

Kinetic Modeling of Quality Changes and Shelf Life Prediction of Dried Coconut Chips

“…The browning index (BI) can be another index that represents the purity of brown and can be used to determine the degree of visible browning in a product in both enzymatic and non-enzymatic staining procedures [15,23]. Furthermore, both an increase in the L* value and a decrease in the a* value are positively correlated to the product's BI value [24][25][26]. According to the results, the BI value of the dried coconut chips (Figure 1e) increased significantly (p < 0.05) as the storage time increased, and the rate of the BI obviously depended on the storage temperature.…”