Kibble Shape and its Effect on

Feline Palatability

Kristopher Figge

Senior Scientist, Technical Services Mgr.

AFB International

Presentation Layout

• Introduction

• Experimental design

• Definitions & Results

• Other related topics

• Comments / discussion

General Items about Cats

• As obligate carnivores, will choose higher protein diets over lower protein diets.

• More likely than dogs to avoid spoilage aromas.

• Lack lateral jaw movement; hence, texture and size are very important.

• Lack molars, and cannot grind their food. Acidification helps salivation.

• Surface texture plays a role in palatability.

– Different breeds of cats pick up their food differently with their tongue.

• In PAL testing, cats tend to consume food from both bowls. First choice is not necessarily linked to total consumption. Feeding time is generally 15 hours.

Factors Affecting Feline PAL

Raw Materials

(Fats, oils, meals, palatants, etc.)

Texture / Size /

Shape

Processing

Hypothesis

Kibble shape affects the PAL of dry

cat food(s).

Experimental Design

• Standard / fixed reference points:

– A finely ground (#3) 34/13, grain-based meal

– Same lot of meal used for all shapes

– All variables coated with the same components

• Fat: 5.0% poultry fat

• Palatant: 1.5% dry cat palatant

– Same moisture specification: 6.5% - 9.5%

– Same density specification: 19 - 24 lbs./ft3

Experimental Design (cont’d)

• Variable(s) in the study:

– Kibble shapes

1) “X” Cross / Star

2) “∆” Triangle

3) “O” Flat Disc

4) Cylinder

5) Triangle w/ center hole

Experimental Design (cont’d)

• What was measured:

– Texture

a) Max. Load c) Energy to Break Pt.

b) Energy to Yield Pt. d) Toughness

– PAL due to kibble shape

a) 2 bowl, paired comparison test

b) 25 cats x 2 days

c) Same panel of cats was used

d) All possible paired tests were done (10)

Equipment

Results

• In-process data

• Kibble shape pictures

• Texture terms & results

• PAL data terms & results

In-Process Data

• Moisture: 6.5% - 9.5%

• Bulk Density: 19 – 24 lbs. / ft3

• Based on In-Process data, all variables were within target

specifications.

ShapeMoisture

(%)

Density

(lbs./ft3)

Diameter

(cm)

Thickness

(cm)

“O” [Disc] 7.40 21.13 0.36 0.19

“X” [Cross] 8.59 22.25 0.54 0.18

“∆” [Triangle] 8.59 23.25 0.45 0.18

Triangle w/ hole 6.96 20.00 0.41 0.20

Cylinder 8.58 21.37 0.32 0.39

Kibble Shape Pictures

Uncoated kibble is shown on the top row; comparable commercial products are on the bottom.

Texture Analysis Terms

• Maximum Load – maximum amt. of force necessary to “fracture” a kibble (measured in kgs of force).

• Energy to Yield Point – energy required to reach a point where kibble begins to fracture (measured in gram•inch).

• Energy to Break Point – energy required to reach a point where kibble finally gives way and fractures completely (measured in gram•inch)

• Toughness – energy to break point divided by gauge length * kibble width * kibble thickness (measured in g/inch2)

Texture Analysis

• Measurements done with an Instron Texture Analyzer

#3342 and Cherry Pitter Needle probe

ShapeMax. Load

(kg-Force)

Energy to Yield Pt.

(gram-inch)

Energy to Break Pt.

(gram-inch)

Toughness

(g/inch2)

“O” [Disc] 5.39 41.46 56.85 227.39

“X” [Cross] 8.08 51.39 69.06 276.23

“∆” [Triangle] 7.06 63.79 100.10 400.41

Triangle w/ hole 2.48 14.07 20.54 82.15

Cylinder 4.23 61.99 145.45 626.90

Maximum Load

4.23

2.48

7.06

5.39

8.08

0

1

2

3

4

5

6

7

8

9

"O" [Disc] "X" [Cross] "∆" [Triangle] Triangle w/

hole

Cylinder

kg

-Fo

rce

Energy to Yield Point

Energy to Break Point

Toughness

Texture Summary

• The Triangle w/ hole had the lowest texture numbers.

• The Cylinder had the highest scores in all categories except

maximum load.

• The “O” [Disc] had the second lowest texture numbers.

• The “X” [Cross] scored in the middle except for max. load

where it had the highest number.

• The “∆” [Triangle] had the second highest scores.

PAL Data Interpretation

• Consumption Ratio (CR): Consumed A / Consumed B

• Intake Ratio (IR-A): Consumed A

(Consumed A + Consumed B)

• First Choice (FC-A): % Animals eating out of Bowl A first

• Preference: Outside the range of 0.45-0.55 IR

• p-Value (p): Probability that A is significantly different from B

(want < 0.05 = 95% confidence level)

“O” [Discs]

Ration A Ration B IR-A CR FC-A PREF p-Value

“X” [Cross / Star] 0.57 1.3A 0.57 10A : 3B 0.013

“∆” [Triangle] 0.47 1.0B 0.55 7A : 9B 0.222

Cylinder 0.64 1.9A 0.39 12A : 2B 0.002

Triangle w/ hole 0.66 2.0A 0.56 12A : 1B 0.000

�“O” > “X”, Cylinder & Triangle-hole

�“O” = “∆”

“X” [Cross / Star]

Ration A Ration B IR-A CR FC-A PREF p-Value

“∆” [Triangle] 0.61 1.5A 0.55 14A : 5B 0.007

“O” [Disc] 0.43 1.3B 0.43 3A : 10B 0.013

Cylinder 0.63 1.7A 0.52 17A : 5B 0.000

Triangle w/ hole 0.56 1.3A 0.50 12A : 6B 0.078

�“X” > Cylinder, Triangle & Triangle-

hole

�“X” < Disc

“∆” [Triangle]

Ration A Ration B IR-A CR FC-A PREF p-Value

“X” [Cross / Star] 0.39 1.5B 0.45 5A : 14B 0.007

“O” [Disc] 0.53 1.0A 0.45 9A : 7B 0.222

Cylinder 0.71 1.5A 0.41 12A : 3B 0.086

Triangle w/ hole 0.51 1.0B 0.57 10A : 9B 0.408

�“∆” > Cylinder

�“∆” = Disc & Triangle-hole

�“∆” < “X”

Triangle w/ Hole

Ration A Ration B IR-A CR FC-A PREF p-Value

“X” [Cross / Star] 0.44 1.3B 0.50 6A : 12B 0.078

“∆” [Triangle] 0.49 1.0A 0.43 9A : 10B 0.408

“O” [Disc] 0.34 2.0B 0.44 1A : 12B 0.000

Cylinder 0.61 1.6A 0.61 11A : 5B 0.028

�Triangle-hole < “O”

�Triangle-hole > Cylinder

�Triangle-hole = “∆” & “X”

Cylinder

Ration A Ration B IR-A CR FC-A PREF p-Value

“X” [Cross / Star] 0.37 1.7B 0.48 5A : 17B 0.000

“∆” [Triangle] 0.29 1.5B 0.59 3A : 12B 0.086

“O” [Disc] 0.36 1.9B 0.61 2A : 12B 0.002

Triangle w/ hole 0.39 1.6B 0.39 5A : 11B 0.028

�Cylinder lost to the other (4)

shapes

Conclusions

• Kibble shape was the primary driver for PAL - texture

across a given range did not drive PAL.– Triangle-hole had the lowest texture scores, but few cats preferred

this shape.

– The “O” [Disc] had mid-range texture scores and was the most

preferred shape.

– The Cylinder was outside the range and was least preferred.

– The “X” [Cross] had slightly more favorable texture scores than the

cylinder; however, its PAL was closer to the “O” [Disc]

– The “∆” [Triangle] had higher texture scores than the “O” [Disc] but

similar PAL

Product Considerations

• The “O” and the “X” had the best overall PAL

– Head-to-head, the “O” was better.

Operations Implications

�The “O” is easier to extrude

•Less potential for die blockage

•↓ drag = ↑ throughput

�The “O” has lower tooling costs

Product Implications

�The “O” is more durable

�The “O” had less fines

�The “O” has more surface area

References

• Royal Canin Almond 11 / Persian cat study

Thank You!

Kristopher Figge

AFB International

Sr. Scientist; Tech. Service Mgr.

Tel: (636) 634-4142

Fax:(636) 634-4644

Email: kfigge@afbinternational.com

Other Contributors:

Pat Moeller, PhD

Amy McCarthy, PhD

Cheryl Murphy

Bola Oladipupo, DA