Sensory and textural changes in maturing Omani dates

Robert M. Myhara, Ahmed Al-Alawi, John Karkalas, Mark S. Taylor

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The astringency and texture of the Omani date variety khalas were examined at progressive levels of maturity. Astringency was measured using descriptive sensory analysis, while texture was measured with a texture meter. The phenolic (referred to as 'tannin') and polygalacturonic acid (referred to as 'pectin') contents of the dates were measured by colorimetry. It was found that astringency closely followed levels of tannin content measured on a fresh weight basis. The most astringent dates were at the kimri and tamar stages of maturity, which also had the highest fresh weight tannin content of 2.8 and 1.5g kg-1 respectively. The least astringent dates were at the rutab stage of maturity, which also had the lowest fresh weight tannin content (1.0g kg-1). On a dry weight basis the tannin content decreased as the dates matured. The texture of the dates closely followed the degree of methylation of the date pectin. The softest dates were at the tamar stage of maturity, with a degree of methylation of 39%, while the hardest dates were at the kimri stage, with a degree of methylation of 72%. The polygalacturonic acid content did not appear to affect the texture, since the fresh weight polygalacturonic acid content was higher at the tamar stage (11-13g kg-1) than at the kimri stage (6-9 g kg-1) of maturity. Traditionally, dates at the rutab stage are preferred since they are considered the sweetest and softest. Although tamar dates have the highest sugar content, owing to moisture loss, rutab dates may be preferred not necessarily for their great sweetness and soft texture, but rather for their lack of astringency.

Original languageEnglish
Pages (from-to)2181-2185
Number of pages5
JournalJournal of the Science of Food and Agriculture
Volume80
Issue number15
DOIs
Publication statusPublished - 2000

Fingerprint

Tannins
dates (fruit)
astringency
texture
tannins
Weights and Measures
Astringents
Methylation
maturity stage
methylation
pectins
acids
Colorimetry
colorimetry
sweetness
sugar content
sensory evaluation
polygalacturonic acid
pectin

Keywords

  • Astringency
  • Dates
  • Maturation
  • Pectin
  • Tannin
  • Texture

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Agronomy and Crop Science
  • Nutrition and Dietetics

Cite this

Sensory and textural changes in maturing Omani dates. / Myhara, Robert M.; Al-Alawi, Ahmed; Karkalas, John; Taylor, Mark S.

In: Journal of the Science of Food and Agriculture, Vol. 80, No. 15, 2000, p. 2181-2185.

Research output: Contribution to journalArticle

Myhara, Robert M. ; Al-Alawi, Ahmed ; Karkalas, John ; Taylor, Mark S. / Sensory and textural changes in maturing Omani dates. In: Journal of the Science of Food and Agriculture. 2000 ; Vol. 80, No. 15. pp. 2181-2185.
@article{4dff4c05c4104d8793482cbda7f74361,
title = "Sensory and textural changes in maturing Omani dates",
abstract = "The astringency and texture of the Omani date variety khalas were examined at progressive levels of maturity. Astringency was measured using descriptive sensory analysis, while texture was measured with a texture meter. The phenolic (referred to as 'tannin') and polygalacturonic acid (referred to as 'pectin') contents of the dates were measured by colorimetry. It was found that astringency closely followed levels of tannin content measured on a fresh weight basis. The most astringent dates were at the kimri and tamar stages of maturity, which also had the highest fresh weight tannin content of 2.8 and 1.5g kg-1 respectively. The least astringent dates were at the rutab stage of maturity, which also had the lowest fresh weight tannin content (1.0g kg-1). On a dry weight basis the tannin content decreased as the dates matured. The texture of the dates closely followed the degree of methylation of the date pectin. The softest dates were at the tamar stage of maturity, with a degree of methylation of 39{\%}, while the hardest dates were at the kimri stage, with a degree of methylation of 72{\%}. The polygalacturonic acid content did not appear to affect the texture, since the fresh weight polygalacturonic acid content was higher at the tamar stage (11-13g kg-1) than at the kimri stage (6-9 g kg-1) of maturity. Traditionally, dates at the rutab stage are preferred since they are considered the sweetest and softest. Although tamar dates have the highest sugar content, owing to moisture loss, rutab dates may be preferred not necessarily for their great sweetness and soft texture, but rather for their lack of astringency.",
keywords = "Astringency, Dates, Maturation, Pectin, Tannin, Texture",
author = "Myhara, {Robert M.} and Ahmed Al-Alawi and John Karkalas and Taylor, {Mark S.}",
year = "2000",
doi = "10.1002/1097-0010(200012)80:15<2181::AID-JSFA765>3.0.CO;2-C",
language = "English",
volume = "80",
pages = "2181--2185",
journal = "Journal of the Science of Food and Agriculture",
issn = "0022-5142",
publisher = "John Wiley and Sons Ltd",
number = "15",

}

TY - JOUR

T1 - Sensory and textural changes in maturing Omani dates

AU - Myhara, Robert M.

AU - Al-Alawi, Ahmed

AU - Karkalas, John

AU - Taylor, Mark S.

PY - 2000

Y1 - 2000

N2 - The astringency and texture of the Omani date variety khalas were examined at progressive levels of maturity. Astringency was measured using descriptive sensory analysis, while texture was measured with a texture meter. The phenolic (referred to as 'tannin') and polygalacturonic acid (referred to as 'pectin') contents of the dates were measured by colorimetry. It was found that astringency closely followed levels of tannin content measured on a fresh weight basis. The most astringent dates were at the kimri and tamar stages of maturity, which also had the highest fresh weight tannin content of 2.8 and 1.5g kg-1 respectively. The least astringent dates were at the rutab stage of maturity, which also had the lowest fresh weight tannin content (1.0g kg-1). On a dry weight basis the tannin content decreased as the dates matured. The texture of the dates closely followed the degree of methylation of the date pectin. The softest dates were at the tamar stage of maturity, with a degree of methylation of 39%, while the hardest dates were at the kimri stage, with a degree of methylation of 72%. The polygalacturonic acid content did not appear to affect the texture, since the fresh weight polygalacturonic acid content was higher at the tamar stage (11-13g kg-1) than at the kimri stage (6-9 g kg-1) of maturity. Traditionally, dates at the rutab stage are preferred since they are considered the sweetest and softest. Although tamar dates have the highest sugar content, owing to moisture loss, rutab dates may be preferred not necessarily for their great sweetness and soft texture, but rather for their lack of astringency.

AB - The astringency and texture of the Omani date variety khalas were examined at progressive levels of maturity. Astringency was measured using descriptive sensory analysis, while texture was measured with a texture meter. The phenolic (referred to as 'tannin') and polygalacturonic acid (referred to as 'pectin') contents of the dates were measured by colorimetry. It was found that astringency closely followed levels of tannin content measured on a fresh weight basis. The most astringent dates were at the kimri and tamar stages of maturity, which also had the highest fresh weight tannin content of 2.8 and 1.5g kg-1 respectively. The least astringent dates were at the rutab stage of maturity, which also had the lowest fresh weight tannin content (1.0g kg-1). On a dry weight basis the tannin content decreased as the dates matured. The texture of the dates closely followed the degree of methylation of the date pectin. The softest dates were at the tamar stage of maturity, with a degree of methylation of 39%, while the hardest dates were at the kimri stage, with a degree of methylation of 72%. The polygalacturonic acid content did not appear to affect the texture, since the fresh weight polygalacturonic acid content was higher at the tamar stage (11-13g kg-1) than at the kimri stage (6-9 g kg-1) of maturity. Traditionally, dates at the rutab stage are preferred since they are considered the sweetest and softest. Although tamar dates have the highest sugar content, owing to moisture loss, rutab dates may be preferred not necessarily for their great sweetness and soft texture, but rather for their lack of astringency.

KW - Astringency

KW - Dates

KW - Maturation

KW - Pectin

KW - Tannin

KW - Texture

UR - http://www.scopus.com/inward/record.url?scp=0034524518&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034524518&partnerID=8YFLogxK

U2 - 10.1002/1097-0010(200012)80:15<2181::AID-JSFA765>3.0.CO;2-C

DO - 10.1002/1097-0010(200012)80:15<2181::AID-JSFA765>3.0.CO;2-C

M3 - Article

AN - SCOPUS:0034524518

VL - 80

SP - 2181

EP - 2185

JO - Journal of the Science of Food and Agriculture

JF - Journal of the Science of Food and Agriculture

SN - 0022-5142

IS - 15

ER -