## Facts

- Grain Processing Corp. (GPC) owned U.S. Patent No. 3,849,194 covering certain starch hydrolysate (maltodextrin-type) products used in food applications.
- The patented products were developed to meet industry demand for a hydrolysate that is cold-water soluble, non-hygroscopic, bland, colorless, and capable of producing clear aqueous solutions over time.
- The patent issued in 1974 after a lengthy prosecution; it included 10 process claims and four product claims (claims 11–14).
- Before trial, GPC withdrew the process claims and proceeded only on product claims 11–14, which described the products by ranges of dextrose equivalent (DE), a descriptive ratio (DR) greater than about 2, and an “exceptional clarity”/long-term clarity requirement.
- American Maize-Products Co. (Maize) sold starch hydrolysate products including ARD 2370, Fro-Dex 5, and Fro-Dex 10, which GPC alleged infringed claims 11–14.
- The district court held claims 11–14 valid; found ARD 2370 infringed; found Fro-Dex 5 and Fro-Dex 10 did not infringe, relying principally on a view that these products failed the patent’s long-term clarity requirement.

## Issues

1. Whether Fro-Dex 10 infringed the asserted product claims (claims 12–14) under the correct construction and application of the “clarity” and DR limitations.
2. Whether claims 11–14 were invalid for anticipation or obviousness in view of the prior art (including Wallerstein).
3. Whether the patent was unenforceable for inequitable conduct based on alleged nondisclosure of prior art and alleged prior public use.

## Decision

- The Federal Circuit affirmed the judgment that claims 11–14 were valid.
- The Federal Circuit reversed the determination that Fro-Dex 10 did not infringe claims 12–14, concluding the district court misapplied the clarity requirement and that Fro-Dex 10 met the relevant claim limitations.
- The Federal Circuit affirmed the remainder of the liability judgment, leaving undisturbed the findings concerning ARD 2370 infringement and Fro-Dex 5 noninfringement.
- The Federal Circuit remanded for the district court to consider whether enhanced damages and attorney’s fees were warranted.

## Legal Principles

- Product claims defined by functional or performance properties must be construed and applied in light of the specification and prosecution history; courts should not narrow property limitations beyond what the intrinsic record supports.
- A prior art reference does not anticipate a property-defined product claim unless it discloses the claimed product, including the claimed combination of performance properties (such as long-term clarity).
- Invalidity for anticipation or obviousness must be proven by clear and convincing evidence; failure of the prior art to teach the claimed combination of properties defeats these challenges.
- Inequitable conduct requires proof of materiality and intent to deceive; negligence, disputed judgment calls about disclosure, or insufficient evidence of intent will not render a patent unenforceable.
- Activities characterized as experimental, rather than commercial exploitation, may not constitute a barring prior public use.

## Conclusion

The Federal Circuit upheld the validity and enforceability of GPC’s property-defined starch hydrolysate product claims and held that, properly construed, Fro-Dex 10 met the claimed clarity and descriptive-ratio limitations, requiring reversal of noninfringement and a remand to consider enhanced damages and attorney’s fees.


Grain Processing Corp. v. American Maize-Prods. Co., 840 F.2d 902 (Fed. Cir. 1988)