Shelf-life study of rice pudding: Differences in assorted rice varieties and how they change in texture over time
(2023) KLTM05 20231Food Technology and Nutrition (M.Sc.)
- Abstract
- This master thesis was performed in collaboration with Orkla Foods Sweden AB. The aim of the study was to investigate rice pudding and how storage time affects the texture properties of the rice grains inside the pudding, and if this could be related to some of the properties of the raw rice. Rice pudding is produced by Orkla Foods under the label Risifrutti and is a popular in-between meal snack in Sweden. Six different rice varieties with different origin or harvest date were selected for investigation and boiled into rice pudding according to a recipe mimicking the factory production process. The texture of the rice grains inside the rice puddings were analyzed on selected days during a 29-day storage period, with the result that all... (More)
- This master thesis was performed in collaboration with Orkla Foods Sweden AB. The aim of the study was to investigate rice pudding and how storage time affects the texture properties of the rice grains inside the pudding, and if this could be related to some of the properties of the raw rice. Rice pudding is produced by Orkla Foods under the label Risifrutti and is a popular in-between meal snack in Sweden. Six different rice varieties with different origin or harvest date were selected for investigation and boiled into rice pudding according to a recipe mimicking the factory production process. The texture of the rice grains inside the rice puddings were analyzed on selected days during a 29-day storage period, with the result that all rice varieties increased in firmness over time to different extent. To investigate what could be the reason for the differences in firmness increase, differential scanning calorimetry (DSC) measurements was performed in parallel with the texture analysis. This was to determine if starch retrogradation could be the cause for the increased grain firmness. It was expected for the DSC to detect endothermic peaks due to starch gelatinization around the starch gelatinization temperature, it was expected for the peaks increase in size over the studied storage period. The starch gelatinization temperature was measured through DSC measurements of the raw rice samples, giving gelatinization temperatures between 66°C and 76°C. Unfortunately, the DSC measurements of the cooked rice pudding grains only detected endothermic reactions around the starch gelatinization temperature in very few of the samples, and then the peaks were very small in size generating rather inconclusive results. Starch could therefore not be said to be the cause for the increased firmness of the cooked rice grains. For the raw rice samples also water absorption, water content and a microscopy study were performed. The water absorption test gave the results that the rice varieties absorbed between 228%-264% of their initial dry weight, and that the rice variety with the highest increase of firmness in the cooked rice grains also had the greatest water absorption. The water content measurements gave that all varieties had between 11.5%-12.7% water content, and the rice variety with the highest water content also had the highest firmness increase in the cooked rice grains.
In conclusion, a rice variety with good water absorption, high water content, and high gelatinization temperature showed the lowest firmness of the cooked rice grains. These are all factors that indicate that the rice variety has a rather low amylose content. To avoid high firmness of the cooked rice grains in the rice pudding, amylose content was deemed to be an important factor when choosing rice variety. However, the firmness of the cooked rice grains is not only dependent on the amylose content but on complex interactions between water, amylose, amylopectin, proteins, and lipids. Factors that all need to be considered to get the wanted rice pudding properties. (Less) - Popular Abstract
- When we eat, we usually don’t think of the chemistry behind the food that we have in front of us, or do you? Every ingredient in your ready meal is carefully selected and tested to fit the taste and texture of the product and to make the product last until its expiration date. The same applies for rice pudding, an in-between meals snack that is easy to consume on the go. Orkla Foods Sweden AB have been producing the Swedish beloved rice pudding under the label Risifrutti since 1992. This thesis was performed in collaboration with Orkla Foods where the aim was to see how the boiled rice grains changed in texture during storage, and if it could be connected to properties of the raw rice. Six rice varieties that differed in origin or harvest... (More)
- When we eat, we usually don’t think of the chemistry behind the food that we have in front of us, or do you? Every ingredient in your ready meal is carefully selected and tested to fit the taste and texture of the product and to make the product last until its expiration date. The same applies for rice pudding, an in-between meals snack that is easy to consume on the go. Orkla Foods Sweden AB have been producing the Swedish beloved rice pudding under the label Risifrutti since 1992. This thesis was performed in collaboration with Orkla Foods where the aim was to see how the boiled rice grains changed in texture during storage, and if it could be connected to properties of the raw rice. Six rice varieties that differed in origin or harvest date were selected for analysis, these were compared by cooking rice pudding from each variety and measure textural changes over one month’s storage time. It was expected that the cooked rice grains should increase in firmness over time, which they did, but to what extent differed between the different rice varieties. It is important that the rice grains inside the rice pudding don’t get to firm before the expiration date since then there is a possibility that the consistency of the rice pudding no longer is pleasant to the consumer. Textural changes within the rice depends on complex interactions between the present water, fat, protein, and carbohydrates, and there are a lot of factors that needs to be considered in order to choose the right raw material. However, measurements performed in this study indicated that the ratio of certain types of carbohydrates present inside the rice was an important factor to be considered when choosing what rice variety to use for the rice pudding production. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9131362
- author
- Bengtsson, Johanna LU
- supervisor
- organization
- course
- KLTM05 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- food engineering, rice starch, rice texture analysis
- language
- English
- id
- 9131362
- date added to LUP
- 2023-06-30 10:50:36
- date last changed
- 2023-06-30 10:50:36
@misc{9131362,
abstract = {{This master thesis was performed in collaboration with Orkla Foods Sweden AB. The aim of the study was to investigate rice pudding and how storage time affects the texture properties of the rice grains inside the pudding, and if this could be related to some of the properties of the raw rice. Rice pudding is produced by Orkla Foods under the label Risifrutti and is a popular in-between meal snack in Sweden. Six different rice varieties with different origin or harvest date were selected for investigation and boiled into rice pudding according to a recipe mimicking the factory production process. The texture of the rice grains inside the rice puddings were analyzed on selected days during a 29-day storage period, with the result that all rice varieties increased in firmness over time to different extent. To investigate what could be the reason for the differences in firmness increase, differential scanning calorimetry (DSC) measurements was performed in parallel with the texture analysis. This was to determine if starch retrogradation could be the cause for the increased grain firmness. It was expected for the DSC to detect endothermic peaks due to starch gelatinization around the starch gelatinization temperature, it was expected for the peaks increase in size over the studied storage period. The starch gelatinization temperature was measured through DSC measurements of the raw rice samples, giving gelatinization temperatures between 66°C and 76°C. Unfortunately, the DSC measurements of the cooked rice pudding grains only detected endothermic reactions around the starch gelatinization temperature in very few of the samples, and then the peaks were very small in size generating rather inconclusive results. Starch could therefore not be said to be the cause for the increased firmness of the cooked rice grains. For the raw rice samples also water absorption, water content and a microscopy study were performed. The water absorption test gave the results that the rice varieties absorbed between 228%-264% of their initial dry weight, and that the rice variety with the highest increase of firmness in the cooked rice grains also had the greatest water absorption. The water content measurements gave that all varieties had between 11.5%-12.7% water content, and the rice variety with the highest water content also had the highest firmness increase in the cooked rice grains.
In conclusion, a rice variety with good water absorption, high water content, and high gelatinization temperature showed the lowest firmness of the cooked rice grains. These are all factors that indicate that the rice variety has a rather low amylose content. To avoid high firmness of the cooked rice grains in the rice pudding, amylose content was deemed to be an important factor when choosing rice variety. However, the firmness of the cooked rice grains is not only dependent on the amylose content but on complex interactions between water, amylose, amylopectin, proteins, and lipids. Factors that all need to be considered to get the wanted rice pudding properties.}},
author = {{Bengtsson, Johanna}},
language = {{eng}},
note = {{Student Paper}},
title = {{Shelf-life study of rice pudding: Differences in assorted rice varieties and how they change in texture over time}},
year = {{2023}},
}