This document describes a study that used a Plackett-Burman experimental design to examine the effects of seven hydrocolloids on the textural properties and glucose dialysis retardation index (GDRI) of meat-based baby foods. Key findings include: 1) locust bean gum and kappa carrageenan increased food matrix force while iota-carrageenan increased pH and decreased acidity; 2) hydrocolloids did not clearly affect GDRI; and 3) locust bean gum showed potential for texture modification with minimal added glucose. The conclusions recommend further study using higher hydrocolloid concentrations and excluding those introducing significant free glucose.

1. Effect of seven hydrocolloids on GDRI
and textural properties of beikosts.
MÁSTER EN NUTRICIÓN,
TECNOLOGÍA Y SEGURIDAD
ALIMENTARIA
2011/2012
ANA CAÑIZARES BEJARANO
DIRECTORA: MARÍA JESÚS PERIAGO CASTÓN

2. INTRODUCTION

3. Glicemic index (GI) was developed by Jenkins et al.
(1981) as method to classify food products based on
their inmediete effects on blood glucose levels.
IMPROVE
-BLOOD GLUCOSE LEVELS
-LIPIDS LEVELS
REDUCE RISK OF
-OBESITY
-TYPE II DIABETES
-CARDIOVASCULAR DISEASES

4. STANDARD CONDITIONS
RESPONSE
INDIVIDUAL
TEST FOOD
CONTROL
GLUCOSE
GI
BLOOD GLUCOSE
RESPONSE AS AREA
UNDER THE CURVE
DETERMINATION OF GLYCEMIC INDEX

5. Problematic of GI
• GI does not take into account the total amount of
carbohydrates per serving
• Some authors expressed the in index by compairing
the GI of a food with white bread.
• There are differences between different comercial
forms of the same food.
• In vivo method
– Complex
– Difficult to carry out
– Intrapersonal variability

6. Nevertheless, THE KNOWLEDGE OF GLYCEMIC INDEX IS IMPORTANT, and in
vitro studies may serve to pinpoint the mechanisms involved in glucose
diffusion.
Adiotomre et al (1990) defined a glucose dyalisis retardation
index (GDRI) to evaluate the effect of fibre on jejunal nutrient
absorption.
Therefore, it is necessary a fast
and easy in vitro method to obtain
information about the glycemic
response of a certain food item.
GLUCOSE DIALYSIS RETARDATION INDEX

7. According to previous experiments carried out to study the GDRI of beikosts,
we have observed that GDRI is highly influenced by the force and adhesivity of
the food matrix, being these textural properties significantly correlated with fat
and protein content (Cañizares and Rincón, data not showed).
PRINCIPAL COMPONENT ANALYSIS
Based on these results, we have considered the objetives
and the experimental design of the present study.

8. OBJETIVES
The aim of this research was:
•To study the effects of seven different hydrocolloids on the
texture properties of a meat based beikost.
•To study the influence of these textural changes in the glucose
dialysis retardation index (GDRI).
The research was conducted using a Plackett-Burman fold-over experimental
design for screening the effects of hydrocolloids on the response, as the
experimental strategy to follow up.

9. MATERIAL AND METHODS

10. Beikost recipe
Ingredients and their proportions used
in the constant part of the beikosts
prototypes
- Alguinate
- Guar gum
- Xanthan gum
- Tara gum
- Locust bean gum
- Iota carrageenan
- Kappa carrageenan
Hydrocolloids were added
according to the Plackett-
Burman experimental design

11. Cooking protocol
All vegetables were cleansed, peeled and chopped in similar size portions.
They were weighed and the cooked using Thermomix TM31
(Vorwerk, Madrid, Spain)

12. Experimental Design
A Placket-Burman fold over experimental design
(PB-d) was used to screen primary effects of
seven factors (hydrocolloids) affecting:
-Textural characteristics.
- Glucose in vitro retardation properties of
beikosts.

13. Symbol Levels
ACF Code Actual -1 +1
Alginate X1
AL
0 0.5
Guar gum X2
GG
0 0.5
Xanthan gum X3
XG
0 0.5
Locust bean gum X4
LG
0 0.5
Tara gum X5
TG
0 0.5
Kappa carrageenan X6
CK
0 0.5
Iota carrageenan X C 0 0.5
Seven apparent critical factors (ACF) considered and experimental ranges expressed
in coded and actual units, considered for the PB fold-over design at resolution IV.
Experimental Design

14. Full Factorial design 2 k
= 2 7
= 128
Fractional factorial design 2 k - p
1/2 Fractional 2 7-1
= 2 6
= 64
1/4 Fractional 2 7-2
= 2 5
= 32
1/8 Fractional 2 7-3
= 2 4
= 16
1/16 Fractional 2 7-4
= 2 3
= 8

15. Experiment nº X 1 X2 X3 X4 X5 X6 X7
1 + + + - + - -
8 - + + - - - +
7 + + - + - - +
3 - - + + + - +
2 - + + + - + -
4 + - - + + + -
5 - + - - + + +
6 + - + - - + +
Plackett-Burman design for 7 F “fold-over” (128 exp.) with 16 exp.
9 + - - + + + -
10 - - + - + + -
11 - + - + + - -
12 + - + + - - -
13 - + + - - - +
14 + + - - - + -
15 + - - - + - +
16 - - - + - + +
R III
R IV

16. Resolution concept in factorial fractional design
Resolution: 1 + order of the lowest interaction that may
be confused with a primary effect.
R
Principal effects
confused with
no
of letter of
the generator
Example Consequences
III second order 3 I = ABC A=BC
IV third order 4 I = ABCD A = BCD
AB = CD
V fourth order 5 I = ABCDE A = BCDE
AB = CDE

17. Experimental design 27−3
(PB-d) used for study the influence of 7 hydrocolloids on IV
beikosts properties.
Randomization helps
to ensure that the
person performing the
experiment does not
reach erroneous
conclusions due to
extraneous sources of
variability.

18. TEXTURE
ANALYSIS
GLUCOSE DIALYSIS
RETARDATION INDEX
QUANTITATIVE
DETERMINATION OF
GLUCOSE
SOLUBLE SOLIDS
ACOHOL INSOLUBLE
SOLIDS
pH
ACIDITY

19. Texture Analysis
Texture analysis was carried out in
the beikosts in order to determine
the main textural characteristics of
the prototypes.
Penetration test was performed in
order to study the textural behavior
of “solid like” samples.
The experiment was performed, at
room temperature (≈25 °C), by
using a TA-XTplus TextureAnalyser
(StableMicroSystems, Godalming,
Surrey, UK), equipped with a 35 mm
diameter cylindrical probe (P/35).

20. SOLUBLE SOLIDS
ALCOHOL INSOLUBLE SOLIDS
ACIDITY pH
F.A.O. Method
described by Boar
(1988)

21. Glucose Retardation Index
SAMPLING EVERY 15’ FOR 2 HOURS
GLUCOSE RETARDATION INDEX WAS
PERFOMED USING A MODIFICATION OF
THE METHOD PROPOSED BY ADIOTOMRE
ET AL. (1988)

22. Quantitave Determination of glucose
Glucose oxidase enzyme (GOD) catalyzes the oxidation of
glucose to gluconic acid and hydrogen peroxide.
Hydrogen peroxide (H2O2) produced in that reaction is
captured by a chromogenic oxygen acceptor, phenol-
aminophenazone in the presence of peroxidase (POD).
The intensity of the color formed is proportional to the
glucose concentration in the sample.
Color measured
at 505nm

23. RESULTS AND DISCUSSION

24. Plackett-Burman experimental design and results obtained for each trial assayed for
AIS (R1), soluble solids (R2), pH (R3), acidity (R4), force (R5), adhesiveness (R6) and
glucose (mg) input by hydrocolloids to 700 gr of beikosts (R7).
Instead of raw variables, codified variables are used in the design in order to ensure that
every factor in the study has the same importance and to avoid confusion during the
analysis. Also, trials were developed randomly to avoid background noise as a cause of
external variability.

25. Effects in terms of coded factors on each response considered for strong effects. A
conventional criterion was considered to define a strong effect such
as p≤ 0.05 and so to identify the factor as an influencing factor (IF).
Alginate
Guar gum
Xanthan gum
Locust bean gum
Tara gum
Kappa carrageenan
Iota carrageenan
Alginate (X1)and tara gum (X5) increase the insoluble solids content in 0.90 and
1.27 units in the same scale which insoluble solids content was measured. On the
other hand, iota- carrageenan (X7), originates a decreasing on that content.
None of the variables seem to have effect, nor positively neither negatively in soluble
solids content.
Also, alginate shows an improvement in pH, while iota-carrageenan improves not only pH
but adhesiveness, and decreases acidity by 0.39 units on the acidity scale used.
Only locust bean (X4) gum and kappa- carrageenan (X6) increased by 2.81 and 2.65 units
respectively on the scale used to measure texture, providing higher values of force in
beikost matrix.
As can easily be seen, iota and kappa-carrageenan are the major contributors to glucose
input to 700 g of beikost.

26. Plackett-Burman experimental design and results obtained for each trial assayed
for GDRI at 15, 30, 45, 60, 77, 90, 105 y 120 minutes.

27. Alginate
Guar gum
Xanthan gum
Locust bean gum
Tara gum
Kappa carrageenan
Iota carrageenan
Effects in terms of coded factors on each response considered for strong effects. A
conventional criterion was considered to define a strong effect such as p≤ 0.05 and
so to identify the factor as an influencing factor (IF). The responses were the
Glucose Dialysis Retardation Index (GDRI) obtained at different times.
Xanthan gum (X3) has a quickening effect in glucose dialysis at 45 minutes. Kappa-
carrageenan (X6) seems to have contradictory effects, retarding glucose dialysis at
75 minutes but showing a quickening effect at the end of the dialysis time.
Results obtained related to GDRI do not agree with the previous hypothesis that
increased textural characteristic may retard glucose diffusion, since the addition of
hydrocolloids do not have a clear behavior on GDRI.
Different but not clear effects were observed after the addition of hydrocolloids on
force and adhesiveness values of samples and in the other parameters. The observed
variability may be related to the difference in origin and composition of used
hydrocolloids.

28. Correlation matrix test between factors and responses.
Iota-carrageenan is strongly and positively correlated with glucose input (mg)
by hydrocolloids in 700g of weaning food. This correlation may be explained
due to the high content of free glucose molecules present in iota hydrocolloid
preparation.
On the other hand, alginate addition is correlated with sample pH.
Iota-carrageenan addition is also negatively related to acidity and positively related to
adhesivity and, both kappa-carrageenan and Locust bean gum are positively correlated
with force although the strength of the correlation index is weak.
Because of that, Locust bean is considered an influencing factor in texture modification
of beikosts
This study provides information about the thickeners addition in textural properties and
GDRI and its possible effect in the GI of foods. We must emphasize the importance of
the selection of the hydrocolloids in order to successfully realize the experimental
design, since the free-glucose presence in some of the hydrocolloids (as iota-
carrageenan), may affect the expected results.

29. CONCLUSIONS

30. • The addition of hydrocolloids lead to non significant texture
modifications of the beikost and hence, no relevant GDRI were
observed. That may be due to the fact that small concentrations of
hydrocolloid were considered for experimental design (0.5 %) and
further experiments should be considered an experimental range
higher and wider (e.g. 0.5- 3.0 %).
• Locus bean appears as the most recommended hydrocolloid to
modify the texture of these foods, because a small amount (0.5%)
have a significant effect on the texture, and also provides a
negligible amount of glucose to beikosts.
• In addition to the previous conclusion, must be taken into
consideration that some hydrocolloids input significant amount of
glucose to beikosts and so and general distortion of results is
obtained. In further experiments tara gum should be excluded and
both kappa and iota-carrageenans should be not considered due to
their similar characteristics.