Andrew Proctor - University of Arkansas, US

Introduction: CLA• Conjugated linoleic acid • Positional and geometrical isomers of linoleic acid • 28 different isomers Adolf, 1999 • Found naturally – Beef – Dairy products... CLA rum

Photocatalytic production and

use of CLA-rich soy oil

A Proctor & V.P JainDepartment of Food Science

University of Arkansas

September 8th 2006 Renewable Resources & Biorefineries Conference

University of York, UK

Introduction: CLA

• Conjugated linoleic acid

• Positional and geometrical isomers of linoleic acid

• 28 different isomers (Adolf, 1999)

• Found naturally – Beef

– Dairy products

CLA rumen biosynthetic pathway

Linoleic acid (cis-9, cis-12 octadecadienoic acid)

cis-9, trans-11 CLA

Vaccenic acid (trans-11 octadecenoic acid)

Rate limiting step ( Lawson et al, 2001)

Stearic acid (Octadecanoic acid)

Health Benefits of CLA

• Anticarcinogenic (Ha and others, 1987)

• Antimutagenic (Yeong and others, 1989)

• Antioxidant (Yeong and others, 1989)

• Decreases atherosclerosis (Ha and Pariza, 1987)

• Decreases body fat (Park and others, 1997)

• Enhances immune system (Yeong and others, 1989)

Health Benefits of CLA

• Human CLA needs are 3g/day to produce

physiological effects (Ip et al 1994)

• Actual human CLA intake 0.3g /day (Ip et al, 1989; Beaulieu et al 2002)

• Increasing dietary animal fat to obtain desirable CLA levels is not recommended

Synthetic CLA

• Methyl esters

– methyl ricinoleate (Berdeaux et al, 1997)

– methyl linoleoate photoisomerization (Seki et al., 1998)

• Vegetable oil linoleic acid

– alkali isomerization (Iwata et al, 1999)

– base conjugation (Delmonte et al, 2003)

– ‘green’ photoisomerization of soy oil

(Gangidi & Proctor, 2004)

Soy Oil for CLA production ?

• Soy oil composition

- 50 % linoleic oil, for conversion to CLA

• Availability

- 34mMT soy oil world supply (2005-2006)*

- 115mMT world vegetable oil supply (2005-2006)*

- 80% of US total oil intake is soy oil

* Oil Crops Situation and Outlook Report 2006

Outline: CLA-rich soy oil

1 Production and oxidative quality

2 Kinetics study

3 Frying study

1 CLA-Rich Soy Oil Production and

Oxidative Quality

J Ag and Food Chem 2006 54: 5590-5596

Customized System

UV Lamp

Customized System

Reaction Vessel

Customized System

Immersion Well

Customized System

Effect of Iodine Concentration – Processing

(Jain & Proctor 2006)

700g fully refined commercial soy oil

CLA isomer: FAME analysis (triplicate)

(Christie & others 2001; Ma & others 1999)

• total CLA

• cis 9, trans 11 CLA

• trans 10, cis 12 CLA

• trans, trans isomers (8,10; 9,11; 10,12)

Lipid oxidation products

• hydroperoxides: ATR FTIR (Ma & others 1999)

• aldehyde carbonyls: 1H NMR (Ma & others 1999)

• GC – MS: hexanal (Monsoor & Proctor 2004)

Effect of Iodine Concentration – Analysis

Effect of iodine concentration on total CLA Yields

Effect of iodine concentration on cis 9, trans 11 CLA

LSD0.05 = 0.05

Effect of iodine concentration on trans 10 cis 12 CLA

Effect of Iodine Concentration on t, t (8,10; 9,11; 10,12) CLA

LSD0.05 = 0.48

Dairy Beef Soy oil (Proctor & Jain 2006)

CLA fatty acid

c-9, t-11 CLA 0.6 0.1 1.8

t-10, c-12 CLA <0.01 0.02 1.7

Total CLA 0.7 0.6 23.8

CLA (%) content of bovine lipids and soy oil

t, t CLA also has major health benefits (Gavino 2002; Lai et al 2005)

Oxidation Analysis

Hydroperoxide peaks absent

ester C=O

1750 cm -1

Hydrocarbons

ATR – FTIR spectra of photoisomerized oil

samples for hydroperoxide peaks

Conjugated = bond

1H NMR spectra of 144 hour photoisomerized oil for proton peaks of aldehyde carbonyl

1H NMR spectra of unirradiated oil of aldehyde

carbonyl proton peaks

8.0 9.0

10.0 11.0

1H NMR spectra of unirradiated oil with

200 ppm hexanal

8.0 9.0

Partial GC - MS chromatograms: hexanal

6.0 5.0

4.0 3.0

2.0

6.0 5.0

4.0 3.0

2.0

6.0 5.0

4.0 3.0

2.0

Unirradiated oil, 0.15 % Iodine

Unirradiated oil with 1 ppm added hexanal, 0.15 % Iodine

144 hours photoisomerized oil sample, 0.15 % Iodine

• trans, trans major isomers produced

• t, t CLA also has health benefits

• c, t & t, c CLA levels greater than in dairy/meat

• long processing time

• ‘apparently’ relatively oxidatively stable:

Significance

*

2 Kinetics

CLA-isomers Irradiation

cis-9, cis-12 linoleic acid

cis-9, trans-11 CLA, trans-10, cis-12 CLA, trans-9, cis-11 CLA, cis-10, trans-12 CLA

trans- , trans- CLA(8,10 : 9,11 : 10,12)

A

B

C

Soy oil C18:2 fatty acid profile during photo-irradiation

CLA-isomers: irradiation

cis-9, cis-12 linoleic acid

cis-9, trans-11 CLA, trans-10, cis-12 CLA, trans-9, cis-11 CLA, cis-10, trans-12 CLA

trans- , trans- CLA(8,10 : 9,11 : 10,12)

A

B

Csecond order kinetics

zero order kinetics

• A to B reaction dependent on LA conc

• B to C reaction is fastest as it achieves the most thermodynamically stable CLA form

Kinetics

3 CLA-rich soy oil and frying

C18 fatty acids in photoisomerized soy oil, and oil extracted

from potato chips fried in CLA-rich soy oil (n=4)

Photoisomerized oil (%) Oil extracted from chips (%)

Means with different letters within rows differ significantly, p<0.05 Fatty acids expressed on total oil w/w basis

bt,t CLA consists of t,8, t,10 CLA, t,9,t,11 CLA & t,10, t,12 CLA

PV of RBD & CLA rich oil &

these oils extracted from potato chips after frying

PV (Meq / 1000g sample)

Oil extracted from chips made with CLA-rich oil 1.0b

Values are means, n=4

Means with different letters within a column differ significantly, p<0.05

• Oil Composition stable at frying temperatures

• FA composition in chip similar to that of oil

• Frying oil and extracted oil was oxidative stabile

Significance

• Pr

RESEARCH ISSUES

ocessing:

inor compounds:

and oxidation compounds:

long processing time, processing modifications: USDA NRI grant 2006-2009