Article Figures & Data
Figures
- Figure 1
Locations within can body sampled for liner and aluminum surface analysis: 1, top of neck, adjacent to seam; 2, tapered portion of can neck; 3, upper can body below the neck; 4, middle can body; and 5, lower can body.
- Figure 2
Hydrogen sulfide (H2S) production by treatment group and wine after four months (top) and eight months (bottom). Boxes represent range of H2S produced across three can liners, stored in duplicate (n = 6 points for each time point, wine, and treatment). ↓ pH, ↓ fSO2, and ↓ mSO2, low pH, low free SO2, and low molecular SO2, respectively; ↑ pH, ↑ fSO2, and ↑ mSO2, high pH, high free SO2, and high molecular SO2, respectively. FR, French rosé; PG, Pinot grigio; RB, bubbly rosé; SB, Sauvignon blanc; WB, white bubbly.
- Figure 3
Hydrogen sulfide (H2S) production by liner (X1, Y2, and Z2) for each of the five Treatment III (high molecular SO2) wines after four months of storage. Error bars represent one standard error of three technical replicates. The asterisks indicate p < 0.05 (analysis of variance). X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
- Figure 4
Hydrogen sulfide (H2S) production from can body (see Figure 1, Location 4) and headspace (see Figure 1, Locations 1 and 2) coupons from three different batches of cans (X1, Y2, and Z2), using the accelerated aging assay in triplicate (technical replicates), measuring at three and 14 days of storage. A negative control (no coupon) produced 0.5 μg/L H2S. Error bars represent one standard error. X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
- Figure 5
Dependence of hydrogen sulfide (H2S) formation on location of coated aluminum coupon (headspace [HS] versus immersed). Treatment 1, two coupons, one in headspace and one immersed; Treatment 2, one intact coupon, partially in headspace and partially immersed; Treatment 3, two coupons, both immersed; and Treatment 4, coupon in HS only. Three technical replicates were tested for each treatment. Error bars represent one standard error. A negative control group produced 0.5 μg/L H2S.
- Figure 6
Hydrogen sulfide (H2S) production for 10 different can types, as well as the underside of the can lid, after three days in accelerated aging conditions with a commercial German Riesling. Three technical replicates for each type of can (represented on the x-axis) were tested. Error bars represent one standard error. The cans were coded with letters V to Z, signifying the can manufacturer, followed by 1 (BPA epoxy), 2 (BPA-NI epoxy), or 3 (acrylic), to signify the liner type. For two of the can sources, multiple production batches (n = 2 or 3) were tested to evaluate batch-to-batch variation (e.g., Y2-2 indicates it is the second batch of BPA-NI epoxy cans from manufacturer Y).
- Figure 7
Can body liner thickness from 10 different can types, as measured by laser-scanning profilometer (n = 3 cans per liner type). Error bars represent one standard deviation. The cans were coded with letters V to Z, signifying the can manufacturer, followed by 1 (BPA epoxy), 2 (BPA-NI epoxy), or 3 (acrylic), to signify the liner type. For two of the can sources, multiple production batches (n = 2 or 3) were tested to evaluate batch-to-batch variation (e.g., Y2-2 indicates it is the second batch of BPA-NI epoxy cans from manufacturer Y).
- Figure 8
Hydrogen sulfide (H2S) formation after three days at 50°C versus inverse liner thickness for epoxy lined cans (BPA and BPA-NI). Each point represents the average H2S for a different liner (n = 8 technical replicates per liner). Error bars represent one standard error.
- Figure 9
Liner thickness measurements by laser-scanning profilometry, measured across the cans (X1, Y2, and Z2). Three technical replicates were analyzed. Error bars represent one standard deviation. X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
Tables
- Table 1
Percentage of sample surface area at different liner thickness cutoffs. The percentages are averages of three technical replicates. Samples were taken from Locations 1 to 5 as shown in Figure 1. X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For two of the can sources, multiple production batches (n = 2 or 3) were tested to evaluate batch-to-batch variation (e.g., Y2-3 indicates the third batch of BPA-NI epoxy cans from manufacturer Y).
- Table 2
Liner thicknesses (in μm) measured by laser interferometry for X1, Y2, and Z2 cans. Values are averages of multiple 1 to 2 mm2 spots around the can interior. Four cans were analyzed at 24 spots in the can body and eight spots in the dome of each can. X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
Supplemental Table 1 Initial composition of wines used in the long-term canning study. TA, titratable acidity; ABV, alcohol by volume.
Supplemental Table 2 Parameters for open circuit potential testing.
Supplemental Table 3 Parameters for electrochemical impedance spectroscopy testing. OCP, open circuit potential; DC, direct current; AC, alternating current.
Supplemental Figure 1 Can body with top and bottom removed.
Supplemental Figure 2 Locations of (A) body and (B) headspace coupons used for accelerated aging testing. Bare aluminum on the cut coupon edges was sealed with hot-melt glue prior to testing, as shown in (C).
Supplemental Figure 3 Experimental design for comparing effects of immersed and nonimmersed aluminum on hydrogen sulfide formation. Four technical replicates of each treatment were performed. HS, headspace.
Supplemental Figure 4 Electrochemical impedance spectroscopy setup with counter electrode on the left, reference electrode in the middle, and the working electrode contacting the bottom of the can. The electrochemical cell is placed inside a grounded Faraday cage.
Supplemental Figure 5 Unused can with no corrosion (left), and used can with visual corrosion in the neck region (right).
Supplemental Figure 6 Visual defects in the polymeric lining of the “moat,” of Y2-2 cans prestorage. Y2-2, Y signifies the can manufacturer; 2 signifies the liner type (BPA-NI epoxy). For two of the can sources, multiple production batches (n = 2 or 3) were tested to evaluate batch-to-batch variation (e.g., Y2-2 indicates it is the second batch of BPA-NI epoxy cans from manufacturer Y).
Supplemental Figure 7 Elemental analysis by x-ray fluorescence (XRF) for Y2 and Z2 cans. Three technical replicates were analyzed. Y2 and Z2, Y and Z signify the can manufacturer; 2 signifies the liner type (BPA-NI epoxy). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
Supplemental Figure 8 Fourier transform infrared-attenuated total reflectance spectra of the three liners (on aluminum substrate) used in the long-term storage experiment (X1, Y2, and Z2). X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
Supplemental Figure 9 Metal exposure ratings (enamel rating) for the three types of cans used in the long-term aging study (n = 48). X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
Supplemental Figure 10 Impedance values at low-frequency (0.05 Hz) for the three can types used in the long-term aging study. Three technical replicates were tested for each can type (n = 9). Error bars represent one standard error. X1, Y2, Z2: X, Y, and Z signify the can manufacturer; 1 and 2 signify the liner type (BPA epoxy and BPA-NI epoxy, respectively). For example, Y2 indicates a BPA-NI epoxy can from manufacturer Y.
Vol 75 Issue 1
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