Clean Label Solutions to Controlling Lipid Oxidation Eric A Decker Department of Food Science University of Massachusetts, Amherst, USA March 27-28, 2018 Itasca, Illinois, USA
Why is Oxidation Important? Off-Flavor Formation: Food Waste Loss of Nutrients: Co-Oxidation Fortification with Bioactive Lipids Formation of Toxic Lipid Oxidation Products Acrolein HNE, HHE Oxidized Sterols
MECHANISM OF LIPID OXIDATION Initiation Lag Phase Formation of first free radicals HOOC 9 10 11 12 13 H Hydrogen Abstraction H + 9 10 11 12 13 Isomerization Step 9 10 11 12 13 9 10 12 13 11
Propagation Addition of Oxygen and Transfer of Free Radical HOOC Pentadiene system from another linoleic acid O O oo H O H O Lipid Hydroperoxide
β Scission Reactions Breakdown of lipid hydroperoxides to volatile compounds 9-Hydroperoxide Linoleic Acid Metals HOOC O H O 9 10 11 12 13 Step 1 HOOC Step 2 A A B O 9 10 11 12 13 B O HOOC H O 9 10 11 octanoate and 12 13 A H 10 HOOC 11 B 12 13 3-nonenal and O 9 H 2,4-decadienal oxononanate
How to Control Oxidation
Impact of Unsaturation on Susceptibility to Lipid Oxidation 18:1 18:2 18:3 20:4 RELATIVE OXIDIZIBILITY 1 10 20 30 40 20:5
Newspapers soaked in linseed oil caused fire due to spontaneous combustion (Hampshire Gazette; Northampton, MA)
Changing Fatty Acid Composition to Slow Oxidation This was one of the main reasons for hydrogenation Remove 18:3 but formed trans Interesterified oil Can produce solid fat with low total saturates Little know about impact on oxidation High Oleic Oils 18:1 = 10 times more stable than 18:2
High Oleic Oils Oil Oleic (%) Polyunsaturated (%) Canola 62 28 High Oleic Canola 70 3 Safflower 14 74 High Oleic Safflower 75 14 Sunflower 20 66 High Oleic Sunflower 75 10
How to Control Oxidation Oxygen Metals Antioxidants Physical Properties Oxidized Fish Oil
Propagation HOOC Pentadiene system from another linoleic acid O O oo Diffusion Limited H O H O
Oxygen Removal in Low Moisture Food Headspace oxygen removal only takes seconds 65% Oxygen reduction
Impact of Oxygen Concentration on Lipid Oxidation Rates in Emulsions Lipid Oxidation TBARS (mmol/kg oil) TBARS oil) 40 35 30 25 20 15 10 5 0 Saturated O 2-40% -77% 0 5 10 15 20 25 30 Storage Time (Days) Storage Time (Days) -58% 93% Reduced O 2 98% Reduced O 2
Removing Oxygen by Sparging or Flushing with Oxygen Dissolved Oxygen (C/C 0 ) 1.2 1.0 0.8 0.6 0.4 0.2 Min AOX Effect Meaningful AOX Effect Nitrogen Sparge Nitrogen Flush *Not a Sealed System Oxidatively Stable MCT O/W Emulsion 0.0 0 5 10 15 20 25 30 35 40 45 50 55 60 Nitrogen Purging Time (min) Time (Minutes) Is oxygen removal a viable antioxidant strategy for emulsions?
Oxygen Absorbing Films Alternative Oxygen Mitsubishi Reduction Method OMAC Iron based O 2 scavenging incorporated in the food package protective gas barrier (aluminum ) O 2 Outside Package O 2 O 2 O 2 O/W Emulsion PET Iron-based O 2 scavenger Polyolefins
Mitsubishi Oxygen Absorbing Film Uses Ferrous Iron to Absorb Oxygen Oxygen removed quickly by film Oxygen Removal stopped lipid oxidation Limitations: Requires liquid for activation Consequences of anaerobic environment
What are the Major Factors Influencing Oxidation Rates Oxygen Metals Antioxidants Physical Properties
Iron Decomposition of Lipid Hydroperoxides Fe +2 + LOOH Fe +3 + Off Flavors Electron Source e.g. Ascorbate
Impact of Chelators on Propanal Formation in Tween 20 stabilized Algal Oil Emulsions Gold Standard
Proteins and Peptides as Antioxidants 18 Peroxides (mm) 16 14 12 10 8 6 4 Control 0.5 mg β-lg/g oil 2.5 mg β-lg/g oil 0.5 mg CTH/g oil 2.5 mg CTH/g oil Proteins 2 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 Time (day) Peptides
Iron Chelating of Proteins and Peptides 300 250 1 mg/ml β-lg 1 mg/ml CTH 200 [Fe], μm 150 100 50 0 Treatment Limitations = Bitterness
Bitterness Scores of Casein Peptides- Glucose Maillard Products Heating time (h) CP / G 1:0.5 CP / G 1:1 CP/G 1:2 CP 0 70.5±4.6 a, A 70.7±4.8 a, A 68.8±4.9 a, A 72.4±4.8 a, A 1 70.3±4.1 a, A 62.5±5.2 b, B 60.3±3.2 b, B 69.8±3.6 a, A 3 60.0±4.5 b, B 51.7±3.7 c, C 50.8±4.8 c, C 68.0±5.3 a, A 6 54.7±4.3 c, B 44.0±3.4 d, C 45.8±3.8 d, C 69.8±5.2 a, A 12 50.0±3.4 c, B 40.1±4.0 d, C 40.0±3.4 e, C 71.0±4.9 a, A Decrease Bitterness without Decreasing Antioxidant Activity Limitation = Chelating Activity Lost at ph < 5.0
What are the Major Factors Influencing Oxidation Rates Oxygen Metals Antioxidants Physical Properties
Free Radical Scavenging Antioxidants CH 3 Act by lowering the energy of free radicals so they are less effective HO H 3 C O H 3 C O CH 3 ROO ROOH CH 3 O CH 3 CH 3 CH 3 CH 3 O CH 3 CH 3 C 16 H 33 H 3 C O C 16 H 33 CH 3 CH 3 CH 3 CH 3 O O CH 3 CH 3 H 3 C O C 16 H 33 H 3 C O C 16 H 33 CH 3 CH 3
Antioxidant Location Location, Location, Location????? Antioxidant paradox was described by Porter (1980) A paradox was suggested because polar antioxidant are most effective in bulk oils while nonpolar antioxidants are best described in oilin-water emulsion
Emulsified Oil Nonpolar antioxidant Polar antioxidant
CH 3 Nonpolar CH 3 CH 3 CH 3 H 3 C O CH 3 OH CH 3 α-tocopherol CH 3 HO CH 3 O Polar H 3 C O CH 3 Trolox OH
Tocopherol = Nonpolar Trolox = Polar Bulk Corn Oil (Huang et al., 1996)
Trolox = Polar Tocopherol = Nonpolar Emulsified Corn Oil (Huang et al., 1996)
Bulk Oil
Antioxidant Activity in Association Colloids Lipid Hydroperoxides (mmol/ Kg oil) 900 800 700 600 500 400 300 200 100 Blank (SSO) SSO w/ 1000 um DOPC SSO w/ 1000 um DOPC +10 um Trolox SSO w/ +10 um Trolox SSO w/1000 um DOPC +100 um Trolox SSO w/ +100 mcirom Trolox 0 0 5 10 15 20 25 30 35 40 Storage time (day) A Lipid Hydroperoxides (mmol/ Kg oil) 900 800 700 600 500 400 300 200 100 Blank (SSO) SSO w/ 1000 um DOPC SSO w/ 1000 um DOPC +10 um TOC SSO w/ +10 um TOC SSO w/ 1000 um DOPC +50 um TOC SSO w/ +50 um TOC SSO w/ 1000 um DOPC +100 um TOC SSO w/ +100 um TOC 0 0 5 10 15 20 25 30 35 40 Storage time (day) A More Polar Trolox is more effective than Tocopherol
Tocopherols Tocopherols are nonpolar antioxidants α-tocopherol is not a very good antioxidant in many foods Mixed tocopherols are a by product of oil refining Contain all tocopherol homologs Tocopherol combinations work better than individual tocopherols
Effect of α-tocopherol and Mixed Tocopherol Isomers (500 ppm) on the Oxidative Stability of Whey Protein- Stabilized Algae Oil-in-Water Emulsions at ph 3.0 Too may syllables??
Rosemary Antioxidants Extraction technologies minimize flavors Very versatile in many products contain many compounds of varying polarity Combination of compounds increases activity Never approved as an antioxidant https://www.kalsec.com/products/herbalox-rosemary-extracts/
Green Tea Water-soluble so good in bulk/frying oils Must be low in chlorophyll to minimize color and stop prooxidant activity in light Lipid soluble derivative are available that may be better in dispersed lipids (e.g. emulsions) Can reduce metals and be a prooxidant in water based foods
Iron Decomposition of Lipid Hydroperoxides Fe +2 + LOOH Fe +3 + Off Flavors Electron Source e.g. Catechins
Prooxidant and Antioxidant Nature of Green Tea Extract Bulk Oil Oil and Water Emulsion Control
Natural Antioxidants Acerola cherry High in organic acids, phenols and vitamin C Main antioxidant activity is vitamin C Vitamin C is normally a prooxidant in many foods by reducing metals Organic acids could decrease metal interactions with vitamin C switching it from a prooxidant to an antioxidant
Antioxidant Blends Combinations of antioxidants often work better than individual antioxidants Antioxidant regeneration Different physical locations Blends are offered by many commercial vendors Often done with expensive antioxidants (aceroloa) to decrease concentrations and control cost Can make for complicated labels with many ingredients
What are the Major Factors Influencing Oxidation Rates Oxygen Metals Antioxidants Physical Properties
Attack Lipid Fe 2+ ROOH RO Fe 2+ ROOH = Fatty Acid Peroxide RO = Alkoxyl Radical
Natural Emulsifiers Quillaja saponin Free Radical Scavenging Properties
Oxidation in Nanoemulsions with Different Emulsifiers Quillaja Saponin
Free Radical Scavenging Activity of Emulsifiers Surfactant ORAC Tween 80 1.1± 0.1c SDS 0.5 ± 0.1d Lecithin 5.4 ± 0.2b Q-Naturale 55.6 ± 1.2a Interfacial Antioxidant
Water Activity Lipid oxidation is strongly influence by water activity Even small changes in aw could extend shelf-life
Sugars as Antioxidant Chemical or Physical (a w ) Activity Control Glucose = Reducing Sugar (1.6%) is more effective
Sugar compared to Synthetic Antioxidants Maltose has similar activity with much less sweetness
Conclusions Lipid oxidation products are becoming a growing public health concern Fish oil capsules Frying oils Clean label antioxidant strategies could include: Better Control of Oxygen Novel Metal Chelators Naturally Occurring Free Radical Scavengers Manipulation of Physical Properties