Co-Crystals of Lactose-Polyphenols Created from Two Food-Related By-products: Cheese Whey and Maize Inflorescences

Maize inflorescences are a polyphenol-rich by-product generated abundantly from corn consumption. Likewise, cheese whey is a lactose-rich by-product vastly produced from the cheesemaking process. This work proposed the use of both by-products to generate lactose-polyphenol co-cocrystals. The methodology was to add maize-inflorescences powder (M-IP) into hot concentrated Chihuahua cheese whey to extract their polyphenols. Then, this supersaturated lactose-polyphenol solution was cooled to induce the co-crystallization of lactose with polyphenols. The crystallization process ended between 60 and 95 min, and the kinetic crystallization parameters were not altered significantly by the presence of maize polyphenols. The type of crystals created were primarily alpha-lactose monohydrated crystals (α-LM) with a small proportion of whey proteins and polyphenols. The polyphenol entrapment efficiency in lactose crystals was 22–30%, obtaining polyphenol concentrations of 7–9 mg/100 g of crystals. The polyphenols entrapped in lactose crystals were mainly phenolic acids like chlorogenic acid and flavonoids like maysin. The presence of polyphenols provided the lactose crystals with antioxidant activity. Additionally, the entrapment of polyphenols into the crystals prevented their degradation by UV-A irradiation. From these results, it can be concluded that it is feasible to add an extra value to lactose by incorporating polyphenols into the crystals using a by-product like maize inflorescence.