Elsevier

Food Chemistry

Volume 129, Issue 3, 1 December 2011, Pages 1139-1147
Food Chemistry

Effect of spray drying and storage on the stability of bayberry polyphenols

https://doi.org/10.1016/j.foodchem.2011.05.093Get rights and content

Abstract

Bayberry juice was spray dried with maltodextrin (DE 10) as a carrier and then stored under different temperature and water activities (aw). The retention of the total phenolic content (TPC) and total anthocaynins (ACN) during the drying process were about 96% and 94%, respectively, suggesting spray drying was a satisfactory technique for drying heat sensitive polyphenols. Under an aw of 0.11–0.44, the TPC and ACN in bayberry powders decreased by about 6–8% and 7–27%, respectively, after 6 months storage at 4 °C; at 25 °C for the same storage period the decreases were between 6–9% and 9–37%, respectively, while at 40 °C the decreases were in the range 7–37% and 9–94%. The anthocyanin component was more readily degraded relative to other phenolic compounds. The results suggest that bayberry powder should be stored at less than 25 °C and aw of 0.33, on account of greater polyphenol stability under such conditions.

Highlights

Spray drying is a good technique for retention of bayberry polyphenols. ► We evaluated the polyphenol stability of bayberry powder during storage. ► Spray dried bayberry powder should be stored at less than 25 °C and aw of 0.33. ► Anthocyanin in bayberry powder is more readily degraded than other phenolic compounds.

Introduction

Bayberry (Myrica rubra Sieb. et Zucc) is a berry fruit originating from China, which was first introduced to Australia in about 2000. Bayberry fruits have a special sweet/sour taste that has made them one of the most popular and valuable fruits in Chinese markets. In China, the fruit has traditionally also been used to treat gastric intestinal problems, such as diarrhoea and gastroenteritis (Chen, 1996). Bayberry fruits are rich in polyphenols, including anthocyanins, flavonols, and phenolic acids (Bao et al., 2005, Fang et al., 2007, Fang et al., 2009). Polyphenols have been demonstrated to act as antioxidants and are assumed to have beneficial health effects for humans (Tomás-Barberán & Robins, 1997). There is evidence that the strong antioxidant capacity of bayberry fruits (Bao et al., 2005), juice (Fang et al., 2009), and jam (Amakura, Umino, & Tonogai, 2000), is highly correlated with their polyphenolic content.

However, bayberry fruits easily decay and are often processed into juice for wider and longer-term consumption (Fang, Zhang, Sun, & Sun, 2006), but bayberry juice colour can show browning deterioration due to enzyme and phenolic reactions in the liquid state (Fang, Zhang, Sun, & Sun, 2007). Another concern that limits the potential application of bayberry polyphenols is that phenolic compounds are generally sensitive to adverse environmental conditions, including unfavourable temperatures, light, pH, moisture, and oxygen, and are therefore susceptible to degradative reactions during product processing and storage. Encapsulation of the bayberry polyphenols and conversion of the liquid bayberry juice into a solid state might potentially increase the stability of the product, and also make it easier to handle for circulation and application.

In the food industry, microencapsulation techniques have been widely used to protect food ingredients against deterioration, volatile losses, or premature interaction with other ingredients (Shahidi & Han, 1993). Various kinds of microencapsulation techniques such as spray drying, spray chilling/cooling, coacervation, extrusion, fluidized coating, liposome entrapment and molecular inclusion, have been developed (Gouin, 2004). Among these, spray-drying is the most commonly used technique, on account of it being a continuous, low cost process that produces dry particles of good quality, and for which the machinery required is readily available. Spray drying is especially useful for the encapsulation of heat sensitive food ingredients, as the drying process is very rapid and the core is heated to temperatures generally much lower than 100 °C (Masters, 1991). As polyphenols are a group of phytochemicals sensitive to heat processing, spray drying might have the potential for the encapsulation of bayberry polyphenols. This technique has been successfully used for the encapsulation of a number of polyphenol rich materials, including black carrot extract (Ersus & Yurdagel, 2007), Hibiscus sabdariffa L. extract (Chiou & Langrish, 2007), soybean extract (Georgetti, Casagrande, Souza, Oliveira, & Fonseca, 2008), grape seed, apple and olive leaf extracts (Kosaraju, Labbett, Emin, Konczak, & Lundin, 2008), and procyanidins (Zhang, Mou, & Du, 2007).

The aim of this study was to develop a spray drying method for encapsulation of bayberry polyphenols. The polyphenol stability and antioxidant capacity of the spray dried products were monitored during 6 months storage under different combinations of temperature and humidity. This study is regarded as having potential for the industrial use of bayberry polyphenols.

Section snippets

Chemicals and solvents

The chemicals gallic acid, cyanidin 3-glucoside, quercetin 3-galactoside, quercetin 3-glucoside, Folin–Ciocalteu’s phenol reagent, and DPPHradical dot (2, 2-diphenyl-1-picrylhydrazyl) were purchased from Sigma–Aldrich (Castle Hill, NSW, Australia). Acetonitrile and methanol (HPLC grade) were purchased from Merck (Darmstadt, Germany), while ethyl acetate and formic acid (analytical grade) were obtained from Ajax Finechem Pty Ltd. (Taren Point, NSW, Australia). Polyphenolic standards were dissolved in

Product recovery, TPC and ACN retention

The spray dried bayberry powder was recovered from the collection vessel only, and any particles deposited on the dryer chamber were discarded. Product recovery was calculated as the ratio of the mass of solids collected from cyclone to the solid mass in the infeed solution (on a dry weight basis). The powders were immediately sealed after collection to prevent subsequent moisture uptake. The water activity and moisture content were then quickly measured after the powder’s temperature dropped

Conclusions

The stability and antioxidant capacity of bayberry polyphenols during spray drying and storage were studied. Bayberry powder was successfully obtained when the juice was spray dried with maltodextrin (DE 10) as the carrier, with inlet and outlet temperatures of 150 °C and 80 °C, respectively. The retentions of total TPC and ACN during drying process were about 96% and 94%, suggesting spray drying was a satisfactory technique for drying heat sensitive polyphenols. Under an aw of 0.11–0.44 and

Acknowledgements

This work was supported by a Postdoctoral Research Fellowship of The University of Queensland, Australia. We thank Professor Daryl Joyce, from the School of Agriculture and Food Sciences, The University of Queensland, and Dr. Garth, from the Maroochy Research Station, Department of Employment, Economic Development and Innovation, Queensland, for providing the bayberry fruits used in the study. The authors also thank Dr. John Schiller of the University of Queensland for his professional proof

References (29)

  • S.R. Georgetti et al.

    Spray drying of the soybean extract: Effects on chemical properties and antioxidant activity

    LWT – Food Science and Technology

    (2008)
  • S. Gouin

    Microencapsulation: Industrial appraisal of existing technologies and trends

    Trends in Food Science and Technology

    (2004)
  • A. Millqvist-Fureby et al.

    An aqueous polymer two-phase system as carrier in the spray drying of biological material

    Journal of Colloid and Interface Science

    (2000)
  • C.A. Rice-Evans et al.

    Antioxidant properties of phenolic compounds

    Trends in Plant Science

    (1997)
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