The effect of different prefreezing treatments on the structure of strawberries before and after jam making

Marjaana Suutarinen (Corresponding Author), Kaisu Honkapää, Raija-Liisa Heiniö, Karin Autio, Mirja Mokkila

Research output: Contribution to journalArticleScientificpeer-review

34 Citations (Scopus)

Abstract

The structural changes in strawberry tissues during prefreezing treatments, freezing, thawing and jam making were studied by means of instrumental textural measurements and by bright-field as well as by Fourier transform infrared microscopical studies and sensory evaluation. Calcium chloride, pectin methylesterase (PME) or crystallized sucrose were used as pretreatment agents before freezing. Calcium chloride and PME treatments were used either at normal air pressure or in a vacuum. In addition, strawberries were dipped in calcium chloride solution after which they were sprinkled with crystallized sucrose. Strawberries were also just sprinkled with crystallized sucrose. Jams made from strawberries treated with CaCl2and PME in a vacuum or with CaCl2and crystallized sucrose, respectively, had the highest firmness values (about twice as great as the reference sample). Firmness of jam berries correlated negatively with firmness of jam media, i.e. jams with firmer strawberries had less firm medium. According to microscopical studies, both CaCl2and PME in a vacuum and CaCl2and sucrose pretreatments, respectively, affected the microstructure of strawberry tissues. These pretreatments seemed to stabilize the vascular tissue and to affect pectin, protein and structural carbohydrate. The use of a vacuum seemed to affect the pretreatment solutions, affording more effective absorption to the cortex and pith and providing stabilization there, especially for pectin and structural carbohydrate. According to sensory evaluation of the jams, different prefreezing treatments were shown to have a significant influence on the sensory attributes evaluated. The textural attributes in particular were statistically significantly different among the strawberry jams: wholeness of the berries in the jam (P<0.001), firmness (P<0.001) and clarity (P=0.001) of the jam medium as well as redness of the jam colour (P<0.05) were different among the strawberry jams analysed.

Original languageEnglish
Pages (from-to)188 - 201
Number of pages4
JournalLWT - Food Science and Technology
Volume33
Issue number3
DOIs
Publication statusPublished - 2000
MoE publication typeA1 Journal article-refereed

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Fragaria
jams
strawberries
Sucrose
Vacuum
Calcium Chloride
pectinesterase
sucrose
firmness
pretreatment
calcium chloride
Freezing
Fruit
Carbohydrates
pectins
Air Pressure
small fruits
sensory evaluation
Fourier Analysis
carbohydrates

Cite this

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title = "The effect of different prefreezing treatments on the structure of strawberries before and after jam making",
abstract = "The structural changes in strawberry tissues during prefreezing treatments, freezing, thawing and jam making were studied by means of instrumental textural measurements and by bright-field as well as by Fourier transform infrared microscopical studies and sensory evaluation. Calcium chloride, pectin methylesterase (PME) or crystallized sucrose were used as pretreatment agents before freezing. Calcium chloride and PME treatments were used either at normal air pressure or in a vacuum. In addition, strawberries were dipped in calcium chloride solution after which they were sprinkled with crystallized sucrose. Strawberries were also just sprinkled with crystallized sucrose. Jams made from strawberries treated with CaCl2and PME in a vacuum or with CaCl2and crystallized sucrose, respectively, had the highest firmness values (about twice as great as the reference sample). Firmness of jam berries correlated negatively with firmness of jam media, i.e. jams with firmer strawberries had less firm medium. According to microscopical studies, both CaCl2and PME in a vacuum and CaCl2and sucrose pretreatments, respectively, affected the microstructure of strawberry tissues. These pretreatments seemed to stabilize the vascular tissue and to affect pectin, protein and structural carbohydrate. The use of a vacuum seemed to affect the pretreatment solutions, affording more effective absorption to the cortex and pith and providing stabilization there, especially for pectin and structural carbohydrate. According to sensory evaluation of the jams, different prefreezing treatments were shown to have a significant influence on the sensory attributes evaluated. The textural attributes in particular were statistically significantly different among the strawberry jams: wholeness of the berries in the jam (P<0.001), firmness (P<0.001) and clarity (P=0.001) of the jam medium as well as redness of the jam colour (P<0.05) were different among the strawberry jams analysed.",
author = "Marjaana Suutarinen and Kaisu Honkap{\"a}{\"a} and Raija-Liisa Heini{\"o} and Karin Autio and Mirja Mokkila",
year = "2000",
doi = "10.1006/fstl.2000.0638",
language = "English",
volume = "33",
pages = "188 -- 201",
journal = "LWT - Food Science and Technology",
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}

The effect of different prefreezing treatments on the structure of strawberries before and after jam making. / Suutarinen, Marjaana (Corresponding Author); Honkapää, Kaisu; Heiniö, Raija-Liisa; Autio, Karin; Mokkila, Mirja.

In: LWT - Food Science and Technology, Vol. 33, No. 3, 2000, p. 188 - 201.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - The effect of different prefreezing treatments on the structure of strawberries before and after jam making

AU - Suutarinen, Marjaana

AU - Honkapää, Kaisu

AU - Heiniö, Raija-Liisa

AU - Autio, Karin

AU - Mokkila, Mirja

PY - 2000

Y1 - 2000

N2 - The structural changes in strawberry tissues during prefreezing treatments, freezing, thawing and jam making were studied by means of instrumental textural measurements and by bright-field as well as by Fourier transform infrared microscopical studies and sensory evaluation. Calcium chloride, pectin methylesterase (PME) or crystallized sucrose were used as pretreatment agents before freezing. Calcium chloride and PME treatments were used either at normal air pressure or in a vacuum. In addition, strawberries were dipped in calcium chloride solution after which they were sprinkled with crystallized sucrose. Strawberries were also just sprinkled with crystallized sucrose. Jams made from strawberries treated with CaCl2and PME in a vacuum or with CaCl2and crystallized sucrose, respectively, had the highest firmness values (about twice as great as the reference sample). Firmness of jam berries correlated negatively with firmness of jam media, i.e. jams with firmer strawberries had less firm medium. According to microscopical studies, both CaCl2and PME in a vacuum and CaCl2and sucrose pretreatments, respectively, affected the microstructure of strawberry tissues. These pretreatments seemed to stabilize the vascular tissue and to affect pectin, protein and structural carbohydrate. The use of a vacuum seemed to affect the pretreatment solutions, affording more effective absorption to the cortex and pith and providing stabilization there, especially for pectin and structural carbohydrate. According to sensory evaluation of the jams, different prefreezing treatments were shown to have a significant influence on the sensory attributes evaluated. The textural attributes in particular were statistically significantly different among the strawberry jams: wholeness of the berries in the jam (P<0.001), firmness (P<0.001) and clarity (P=0.001) of the jam medium as well as redness of the jam colour (P<0.05) were different among the strawberry jams analysed.

AB - The structural changes in strawberry tissues during prefreezing treatments, freezing, thawing and jam making were studied by means of instrumental textural measurements and by bright-field as well as by Fourier transform infrared microscopical studies and sensory evaluation. Calcium chloride, pectin methylesterase (PME) or crystallized sucrose were used as pretreatment agents before freezing. Calcium chloride and PME treatments were used either at normal air pressure or in a vacuum. In addition, strawberries were dipped in calcium chloride solution after which they were sprinkled with crystallized sucrose. Strawberries were also just sprinkled with crystallized sucrose. Jams made from strawberries treated with CaCl2and PME in a vacuum or with CaCl2and crystallized sucrose, respectively, had the highest firmness values (about twice as great as the reference sample). Firmness of jam berries correlated negatively with firmness of jam media, i.e. jams with firmer strawberries had less firm medium. According to microscopical studies, both CaCl2and PME in a vacuum and CaCl2and sucrose pretreatments, respectively, affected the microstructure of strawberry tissues. These pretreatments seemed to stabilize the vascular tissue and to affect pectin, protein and structural carbohydrate. The use of a vacuum seemed to affect the pretreatment solutions, affording more effective absorption to the cortex and pith and providing stabilization there, especially for pectin and structural carbohydrate. According to sensory evaluation of the jams, different prefreezing treatments were shown to have a significant influence on the sensory attributes evaluated. The textural attributes in particular were statistically significantly different among the strawberry jams: wholeness of the berries in the jam (P<0.001), firmness (P<0.001) and clarity (P=0.001) of the jam medium as well as redness of the jam colour (P<0.05) were different among the strawberry jams analysed.

U2 - 10.1006/fstl.2000.0638

DO - 10.1006/fstl.2000.0638

M3 - Article

VL - 33

SP - 188

EP - 201

JO - LWT - Food Science and Technology

JF - LWT - Food Science and Technology

SN - 0023-6438

IS - 3

ER -