Hazelnut-Finished Pork in the Upper Midwest: A New High-Value Product From A Sustainable Production System

Progress report for ONC19-056

Project Type: Partnership
Funds awarded in 2019: $39,777.00
Projected End Date: 02/28/2022
Grant Recipient: Bayfield County UW-Extension
Region: North Central
State: Iowa
Project Coordinator:
Jason Fischbach
Bayfield County UW-Extension
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Project Information

Summary:

With the recent development of improved hazelnut germplasm for growers in the Upper Midwest, the industry is poised for rapid expansion.  To facilitate this expansion the University of Wisconsin launched the Hazelnut Processing Accelerator in partnership with Northland College, the American Hazelnut Company, the Main Street Project, and the Bayfield Regional Food Producers Cooperative.  The purpose of the Accelerator is to develop processing technology and equipment optimized to hazelnuts grown in the Upper Midwest while providing a bridge processing facility until production volumes are sufficient to support a financially viable facility.  With more than two years of processing experience, we have identified waste streams that are not suitable for human food or require further processing that is too expensive at this time.  Such waste streams may be suitable for livestock feed.

This project will evaluate the feed quality of undersized nuts, half-cracked nuts, and mixtures of the kernel and shell fragments and conduct a feeding trial with pigs to quantify the effect of the feeds on carcass and meat quality.  Such information will allow pork producers and hazelnut growers in the Upper Midwest to capitalize on the growing market for mast-finished regional pork.

Project Objectives:
  1. Analyze the nutritional components of hazelnut screenings including: ground whole undersized nuts, half-cracked nuts, three mixtures of shell and kernel fragments.
  2. Evaluate the growth performance and meat quality of pigs finished with hazelnuts.
  3. Develop and publish a feeding program for hazelnut growers and pork producers for finishing pigs with hazelnuts.
  4. Conduct a consumer-preference and tasting survey for hazelnut-finished pork. (Note: conducting a sensory panel and tasting survey won't be possible due to Covid-19 restrictions and problems with processing capacity at area processing facilities).

Cooperators

Click linked name(s) to expand/collapse or show everyone's info
  • Jeff Jensen (Educator)

Research

Materials and methods:

The first step of the project was to aggregate in-shell hazelnuts from Midwestern producers.  To do so, we partnered with the American Hazelnut Company in Ashland, WI.  Their cracking and cleaning line does not easily handle hazelnuts with 10mm and small hazelnuts.  So, for this project we sorted out all the 10mm in-shell nuts from their line and then supplemented those with in-shell nuts (of all sizes) we purchased from other growers.  Because of the challenge of cracking and cleaning such small hazelnuts we wanted to evaluate the feed quality and growth responses to whole in-shell hazelnuts when ground up.

The feed component data compared to soybeans are show on slides 4 and 5 of the presentation: Lammers - 2020 - Hazelnut Finished Pork.  As the data show, hazelnut kernels have much higher fat, protein, and oleic acid content than soybeans, but when the shells are included the feed value drops significantly. The purpose, then, of our feeding trials was to evaluate the growth and carcass quality of pigs fed whole ground hazelnuts compared to a standard corn/soy diet.

In 2019, we conducted two feeding trials as described here.  Hazelnut kernels, shells, and undersized (diameter < 0.4 in) in-shell hazelnuts were analyzed using standard wet-chemistry techniques for feed analysis. The two feeding trials were conducted to evaluate the effect of diluting pig diets with ten percent in-shell hazelnuts. In each trial, 36 barrows (128 ± 2 lb) were sorted into 6 pens inside of the three mini-hoop barns (48 ft2/pig). Pens of pigs were randomly assigned to receive a balanced corn-soybean meal diet (control) or the control diet diluted with in-shell hazelnuts (90:10 control:in-shell hazelnuts). Hazelnuts were pulverized using a roller mill before incorporation into the diet. Pigs were individually weighed every 28 days and feed disappearance was recorded. For each trial, all pigs were harvested on the same day after either 68 or 69 days of feeding. Two chops were collected from each pig to assess pork quality. One cube (1 in2) of fat was removed from half of the chops (1 sample/pig) and analyzed for fatty acid profile.

Research results and discussion:

The nutrient profile of hazelnut products are summarized in Table 1 and compared to reference values for corn grain and soybean meal. Hazelnut kernels are rich in unsaturated fatty acids particularly oleic (C18:1). In-shell hazelnuts have less crude fat and lower concentrations of specific fatty acids than hazelnut kernels but more than corn grain or soybean meal. Due to the shells, all fiber measures of the in-shell hazelnuts were much greater than the hazelnut kernels, corn grain, or soybean meal.

Pig performance and carcass characteristics are shown in Table 2. Growth rate, carcass weight, and carcass fat were not different across dietary treatment. Pigs fed diets diluted with 10% in-shell hazelnuts grew less efficiently requiring 6% more feed per unit of gain.

Quality characteristics of loin chops and fatty acid profile of backfat is presented in Table 3. Pork quality attributes were not different across dietary treatments. The fat from pigs fed diets containing in-shell hazelnuts had less saturated fat and more unsaturated fat. Oleic acid content was higher in the fat of pigs fed diets containing 10% in-shell hazelnuts as compared to the control diet.

Feeding in-shell hazelnuts to pigs may be an effective way to add value to nuts ill-suited for processing into products for human consumption. Acorn-finished pork is a high-value niche product in several parts of the world. The fatty acid profile of pork fat from acorn-fed pigs also has an elevated concentration of oleic and other monounsaturated fatty acids. Although fat from acorn-finished pigs is reported to have higher amounts of oleic acid than observed in this trial, feeding corn-soybean meal diets diluted with 10% in-shell hazelnuts effectively changed the fatty acid profile of pork fat. The optimal balance point among hazelnut feeding level, pig performance, pork quality, and shelf-life of pork remains to be determined.  Additional feeding trials are planned to evaluate the effects of higher substitution rates of hazelnut in the corn/soy ration.

Restrictions due to Covid-19 in 2020 prevented us from conducting the planned sensory tasting analysis.  Although we will attempt to do a sensory panel analysis in 2021 with pork harvested from the summer trials, we currently don't have permission to do so at UW-Platteville due to Covid-19 restrictions.  Furthermore, UW-Platteville and Iowa State restrictions do not allow us to sell or provide pork harvested from the trial animals to the general public for consumer testing.  We have also not been able to secure processing dates for animals even if we fed them hazelnuts outside the university feeding trials.  As such, we are not planning to conduct the consumer tasting surveys.  Instead, our focus will be on providing research-based on growth rate and meat quality data to producers.

Table 1. Nutrient profile of hazelnut products and reference feedstuffs for pigs.

 

Hazelnut1

Corn2

Soybean Meal3

 

Kernels

Shells

< 0.4 in-shell nut

 

 

Dry matter, %

100.0

100.0

100.0

100.0

100.0

Crude protein, %

18.4

1.3

7.6

9.3

53.0

Lysine, %

0.5

0.0

0.2

0.3

3.3

Crude fiber, %

4.8

75.4

49.5

2.2

4.3

NDF, %

12.2

96.8

68.7

10.3

9.1

ADF %

9.9

81.3

56.7

3.3

5.9

Crude fat, %

61.2

 < 0.1

21.1

3.9

1.7

 

Fatty acids, % of total fat

   Palmitic (C16:0)

4.0

3.8

12.0

7.9

   Oleic (C18:1)

77.1

74.9

26.3

16.3

   Linoleic (C18:2)

16.0

18.0

44.2

39.8

   Saturated

6.0

6.2

13.6

10.8

   Unsaturated

93.5

93.6

72.0

61.4

1 Hazelnut kernels, shells, and < 0.4 in whole nuts were 3.88, 9.34, and 6.02% moisture as fed

2 Corn grain was 11% moisture as fed

3 Soybean meal was 10% moisture as fed

Table 2. Growth performance and carcass characteristics of pigs fed 0 or 10% in-shell hazelnuts.

 

Dietary Treatment

 

 

 

Control

Hazelnut

SEM

P-value

Start weight, lb

128.0

128.0

1.6

0.86

End body weight, lb

286.6

284.4

3.1

0.44

Average daily gain, lb/d

2.3

2.3

< 0.1

0.37

Average daily feed intake, lb/d

8.2

8.6

< 0.1

0.36

Feed –to– Gain

3.5

3.8

< 0.1

0.03

Hot carcass weight, lb

216.0

217.0

3.5

0.79

10th rib back fat, in

1.52

1.52

0.1

0.97

Last rib fat depth, in

1.35

1.30

< 0.1

0.41

1 Diets were a common corn-soybean meal diet diluted with either 0% (Control) or 10% (Hazelnut) rolled in-shell hazelnuts

Table 3. Quality characteristics loin chops and fatty acid profile of backfat from pigs fed 0 or 10% in-shell hazelnuts.

 

Dietary Treatment

 

 

 

Control

Hazelnut

SEM

P-value

Color

3.01

3.01

0.04

0.93

pH

5.75

5.78

0.02

0.17

Marbling, %

1.80

1.71

0.09

0.70

Warner-Bratzler Shear Force

3.51

3.51

0.11

0.99

Cook Loss, %

17.00

16.70

0.60

0.75

 

 

 

 

 

Fatty Acid Composition

 

 

 

 

   Myristic acid (C14:0)

1.43

1.37

0.08

0.58

   Palmitic acid (C16:0)

25.60

24.60

0.25

0.01

   Palmitoleic acid (C16:1)

1.92

1.72

0.08

0.07

   Stearic acid (C18:0)

14.30

13.50

0.37

0.14

   Oleic (C18:1)

41.00

43.30

0.47

< 0.01

   Linoleic (C18:2)

8.46

8.89

0.28

0.25

   Linolenic (C18:3)

0.35

0.33

0.01

0.16

   Saturated fatty acids

42.00

39.80

0.55

< 0.01

   Monounsaturated fatty acids

45.40

47.50

0.49

0.01

   Polyunsaturated fatty acids

9.34

9.81

0.29

0.26

1 Diets were a common corn-soybean meal diet diluted with either 0% (Control) or 10% (Hazelnut) rolled in-shell hazelnuts

Participation Summary

Educational & Outreach Activities

2 Webinars / talks / presentations

Participation Summary:

126 Farmers
16 Ag professionals participated
Education/outreach description:

The project involves two feeding trials: one held during the summer of 2019 and the other held over the early-winter of 2019 and 2020.  The first trial and analysis of the trial was completed in time for the 2020 Upper Midwest Hazelnut Growers Conference (March 6-7) and the Midwest Organic Pork Conference March 13 and 14.  Pete Lammers presented the results from the first trial at both conferences.

Learning Outcomes

66 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key changes:
  • Per the conference evaluation at the Upper Midwest hazelnut growers conference, farmers reported an increased knowledge of the effect of adding ground-up in-shell hazelnuts to a hog ration.

Project Outcomes

Project outcomes:

The two feeding trials found that a corn/soy ration with a 10% inclusion of ground-up in-shell hazelnuts slightly reduced feed conversion efficiency with the hazelnut-finished pigs needing 6% more feed per unit of gain.  The inclusion of hazelnuts did not change the meat quality attributes, but did change the chemical composition of the fat in the tested pork chops.  Fat from the hazelnut finished pigs had less saturated fat and more unsaturated fat. Oleic acid content was higher in the fat of pigs fed diets containing 10% in-shell hazelnuts as compared to the control diet.

Although the feeding aspect of the second trial was completed, Covid-19 restrictions during 2020 prevented us from conducting the sensory tasting analysis with human tasters.  With a one year extension our plan is to conduct another series of feeding trials starting in May to evaluate changes in meat quality in response to higher hazelnut inclusion rates in the feed.  Our hope is to conduct the sensory panel tasting, but at this point Covid-19 restrictions will not allow it, thus we can't guarantee the tasting will be done.  We also will not be able to do the customer evaluations as we are not allowed to distribute the pork harvested from the University trials to the general public.  We considered feeding pigs outside of the trials, but we have not been able to secure processing dates for when the pigs would be ready.

Recommendations:

The hazelnut inclusion did change the fat in the hogs such that it had higher oleic acid.  This means the fat is less solid at room temperature.  This can create problems when processing and cooking the meat.  At the 10% level, the change was not detrimental, but it would be good to conduct further trials to determine the upper limit. It would also be interesting to evaluate a poultry ration with hazelnuts to determine how it affects the eggs and meat.  Feeding a mix of shell and split hazelnuts (a waste product from processing) to chickens would be easier because they can more effectively pick through it for the kernel.   With pigs we have to grind it all up and they are therefore fed a fair amount of indigestible shell.

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.