Effects of freeze drying and hot-air drying on the physicochemical properties and bioactivities of polysaccharides from Lentinula edodes

doi:10.1016/j.ijbiomac.2019.12.222

International Journal of Biological Macromolecules

Volume 145, 15 February 2020, Pages 476-483

https://doi.org/10.1016/j.ijbiomac.2019.12.222 Get rights and content

Highlights

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Polysaccharides were purified from L. edodes (LEP) dried with FD and HD process.
•
Drying methods affected the physicochemical properties and bioactivities of LEP.
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FD treated LEP showed a stronger scavenging ability on ABTS⁺ radical.
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HD treated LEP had a higher immunomodulatory activity for macrophages.

Abstract

Fresh Lentinula edodes were dried using two process technologies—freeze drying (FD) and hot-air drying (HD). The physicochemical, antioxidant and immunomodulatory properties of purified polysaccharides from dried L. edodes (LEP) were then comparatively investigated. Two neutral polysaccharides (FLEP-1 and HLEP-1) and two acidic polysaccharides (FLEP-2 and HLEP-2) were obtained by DEAE-52 cellulose column. The HD treated LEP had higher levels of uronic acid than that of the FD treated LEP. The molar ratios of monosaccharides in FLEP-1, FLEP-2, HLEP-1 and HLEP-2 were different. Moreover, HD treated LEP had more galactose and less glucose. The (1 → 3)-α-glucan structure was dominant in the two neutral polysaccharides, whereas the (1 → 6)-β-glucan was dominant in the two acidic polysaccharides. Hot-air drying could thus promote the α-configuration in neutral polysaccharides while reducing the β-configuration in acidic polysaccharides. FLEP-1, FLEP-2, HLEP-1 and HLEP-2 had potential scavenging capacity against the ABTS radical dot ⁺, whereas freeze-dried polysaccharides exhibited a stronger scavenging ability than that of hot-air dried polysaccharide. LEP could improve immunity by inducing the secretions of NO, TNF-α and IL-6, whereas hot-air drying improved the immunomodulatory activity of LEP. Our results suggested that freeze drying and hot air drying could be appropriately used to obtain functional polysaccharides from L. edodes.

Introduction

Lentinula edodes, known as the shiitake mushroom, was the second most cultivated mushroom in the world [1]. The shiitake mushroom was very popular in many countries, and its cultivation has been established in Asia, North America, Australia and Europe [2]. L. edodes contained several bioactive compounds, including polysaccharides, dietary fiber, ergosterol, and phenols [3,4]. It has been reported that L. edodes has medicinal values such as reducing the incidence of hypercholesterolemia, hypertension, rickets and cancer [5,6]. It has also been reported that polysaccharides were the main bioactive components in L. edodes with many pharmacological activities such as antioxidant, antitumor, and immunomodulatory activities [[7], [8], [9], [10]]. The purified polysaccharide from L. edodes, a type of branched 1-6,1-3-β-D-glucan [7], was often named lentinan. Thus to far, lentinan has been used as a drug for cancer treatment in many countries [[11], [12], [13]].

Drying was a widely used technique that extended the shelf life of fresh shiitake mushrooms by reducing their moisture content. Various drying methods, such as hot-air drying, vacuum drying, microwave drying, freeze drying, and infrared drying have been used in the production of dehydrated mushrooms [1,14]. However, the drying process was reported to affect the bioactivities of polysaccharides as well as their physicochemical properties of polysaccharides such as chemical composition, monosaccharide composition, molecular weight, and structural conformation [[15], [16], [17]]. Appropriate drying methods to use in the production of bioactive polysaccharides continued to be of great interest. Ma, Chen, Zhu and Wang [16] reported that freeze dried polysaccharides from mushroom Inonotus obliquus showed significant antioxidant activities. Similar results were also reported by Fan, Li, Deng and Ai [18] regarding polysaccharides from the Ganoderma lucidum mushroom. Hot air drying is currently the most extensively used method in the food industry and has been used to obtain bioactive polysaccharides from acorns [19]. However, there are few reports about the effects of different drying technologies on the properties of polysaccharides from L. edodes.

Thus, the aim of this study was to extract and separate neutral and acidic polysaccharides from dried L. edodes (LEP) treated with FD and HD, respectively. The physicochemical and structure properties of different kinds of LEP were investigated. The bioactivities of LEP, including antiradical, immunomodulatory, and antitumor capacities were also determined.

Section snippets

Materials

Fresh L. edodes was purchased from a mushroom farm in Suizhou, Hubei Province, China. All the reagents used were of analytical grade.

Preparation of dried L. edodes

The fresh L. edodes mushrooms were cut into pieces and separately dried by hot-air drying and freeze drying methods. The hot-air drying group was kept at 60 °C for 5 h in a drying oven (CT-C, Changzhou Yineng Instrument Co., Ltd., China). The freeze dried group was treated with a freeze drier (Betr 2-8 LD plus, Christ, Germany) for 48 h. The moisture content of

Physicochemical properties of LEPs

The physicochemical properties of FLEP-1, FLEP-2, HLEP-1 and HLEP-2 are shown in Table 1. The four types of LEPs were found to have high sugar content (89.03%–91.87%). There was no significant difference among the total sugar levels of LEPs. Generally, the results indicated that the four types of polysaccharides were pure for further study. HLEP-1 had lower protein content than that of FLEP-1 (4.15%), FLEP-2 (3.95%), and HLEP-2 (4.35%). The results showed that the uronic acid content in acidic

Conclusion

In the present study, the effects of various drying technologies, including freeze drying and hot-air drying on the physicochemical properties, main structural characteristics, antioxidant activity, and immunoenhancing properties of LEP were investigated. Two kinds of neutral polysaccharides with (1 → 3)-α-glucan backbones and two kinds of acidic polysaccharides with (1 → 6)-β-glucan backbones were successfully purified from dried L. edodes. Our results showed that different drying methods

CRediT authorship contribution statement

Ying Liu: Conceptualization, Data curation, Writing - original draft, Visualization, Supervision. Menglin Luo: Methodology, Investigation, Data curation. Feng Liu: Methodology, Investigation, Data curation. Xi Feng: Writing - review & editing. Salam A. Ibrahim: Writing - review & editing. Lei Cheng: Resources, Funding acquisition. Wen Huang: Supervision, Resources.

Declaration of competing interest

The authors declare no competing financial interest.

Acknowledgements

The authors are grateful for the Open Fund from the Beijing Advanced Innovation Center for Food Nutrition and Human Health (No. 20181047) and the Major Project of Technological Innovation Special Fund of Hubei Province (2017ABA148).

References (51)

Y. Tian et al.
Effects of different drying methods on the product quality and volatile compounds of whole shiitake mushrooms
Food Chem.
(2016)
Y. Liu et al.
Purification and characterisation of two enzymes related to endogenous formaldehyde in Lentinula edodes
Food Chem.
(2013)
H. Zhuang et al.
Characterization of Lentinus edodes β-glucan influencing the in vitro starch digestibility of wheat starch gel
Food Chem.
(2017)
Z. Xue et al.
Structure, thermal and rheological properties of different soluble dietary fiber fractions from mushroom Lentinula edodes (Berk.) Pegler residues
Food Hydrocoll.
(2019)
T. Sasaki et al.
Further study of the structure of lentinan, an anti-tumor polysaccharide from Lentinus edodes
Carbohydr. Res.
(1976)
X. Xu et al.
Chain structures of glucans from Lentinus edodes and their effects on NO production from RAW 264.7 macrophages
Carbohydr. Polym.
(2012)
J. Bai et al.
Physiological functionalities and mechanisms of β-glucans
Trends Food Sci. Technol.
(2019)
D. Kothari et al.
Anticancer and other therapeutic relevance of mushroom polysaccharides: a holistic appraisal
Biomed. Pharmacother.
(2018)
Q. Wang et al.
Quality evaluation and drying kinetics of shitake mushrooms dried by hot air, infrared and intermittent microwave–assisted drying methods
LWT
(2019)
E.I. Nep et al.
Physicochemical characterization of grewia polysaccharide gum: effect of drying method
Carbohydr. Polym.
(2011)

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Effects of freeze drying and hot-air drying on the physicochemical properties and bioactivities of polysaccharides from Lentinula edodes

Highlights

Abstract

Introduction

Section snippets

Materials

Preparation of dried L. edodes

Physicochemical properties of LEPs

Conclusion

CRediT authorship contribution statement

Declaration of competing interest

Acknowledgements

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