Anthocyanins from blackberry (Rubus fructicosus L.) impregnated in yam bean (Pachyrhizus erosus (L.) Urb.) by osmotic dehydration

Alicia Grajales-Lagunes,Miguel Angel Ruiz-Cabrera,Federico Gutiérrez-Miceli,Luc Dendooven,Miguel Abud-Archila,Luis Cabrera-Ruiz

doi:10.1590/fst.15618

Abstract

Abstract Yam bean (Pachyrhizus erosus (L.) Urb.) tuber has a low carbohydrate content and contains several aminoacids, but contains few active compounds, such as vitamins and antioxidants. Anthocyanins are antioxidants found in Rubus fructicosus L. The osmotic drying is a technique that can be used to impregnate antioxidants in a matrix, so the objective of this study was to impregnate yam bean tuber slices with anthocyanin. The effect of temperature (40, 50 and 60oC), sucrose content (40, 50 and 60oBrix) and vacuum pulse (0, 300 and 600 mbar) on water loss (WL), solid gain (SG), color changes (ΔE) and anthocyanin concentration (ΔA) during osmotic drying of yam bean slices was determined. Polynomial equations were used to determine changes in WL, SG, ΔE and ΔA of yam bean slices after 6 h of osmotic drying. An osmotic solution at 60oC with a SC of 40oBrix, applying a vacuum pulse of 12 mbar maximized anthocyanin impregnation (6.67 mg anthocyanin per g initial dry matter) in tuber slices. The Page equation predicted optimum WL, SG and ΔA of yam bean tuber slices during osmotic drying. No relation was found between temperature, sucrose content and vacuum pulse with K and n parameters in the Page equation.

Highlights

Yam bean (Pachyrhizus erosus (L.) Urb.) is a tuber with a high water content, large amounts of carbohydrates, crude fibers and proteins and a negligibly lipid content
Zapata et al (2016) optimized the vacuum pulse osmotic dehydration of cape gooseberry (Physalis peruviana L.). They found that using a sucrose solution of 70oBrix at 45°C, applying an agitation of 99.99 rpm with a pressure of 98.92 mbar and 2.87 vacuum pulses reduced weight 47.5% and water loss 21.1%, while the solid gain was 118.4%
The osmotic drying process allowed to impregnate yam bean tuber slices with anthocyanin from R. fructicosus juice

Summary

Introduction

Yam bean (Pachyrhizus erosus (L.) Urb.) is a tuber with a high water content, large amounts of carbohydrates, crude fibers and proteins and a negligibly lipid content. The total caloric value of yam bean tubers is 39 kcal/100 g (Noman et al, 2007), so they could be used in diets that require a low amount of calories. Yam bean tubers can be used as a solid matrix to impregnate them with nutritious components. Berries play an important role in human nutrition as they contain bioactive compounds, such as anthocyanins and phenolic acids (Manganaris et al, 2014). Some of these compounds have antioxidant properties (Wang & Lin, 2000; Wu et al, 2002) with a large nutritional value (Zhang et al, 2004). Yam bean tuber could be impregnated with juice of R. fructicosus sp. Yam bean tuber could be impregnated with juice of R. fructicosus sp. thereby increasing its nutritional value (Shi & Le Maguer, 2002)

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Conclusion