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: [email protected]
Other Contributors:
Pat Moeller, PhD
Amy McCarthy, PhD
Cheryl Murphy
Bola Oladipupo, DA