Here’s some information about Porcelana cocoa and other white-coloured cocoa beans:
Back in 1957, Raffaele and Fiorella Ciferri published an article titled “The Evolution of Cultivated Cacao” (Evolution, Vol.11, no.4, pp.381-397).
In this article, the authors use the name Porcelain (they mention that the name is “Porcelano” or “Porcelana” in Spanish). They say that the Porcelain is “an unusual, localized and rare type” which is indigenous to Venezuela. They state that Porcelain cocoa is “supposed to be an albino mutant of Amazonian Forastero or Calabacillo”.
This claim seems totally plausible, because it is well documented that Forastero trees can and do produce pure white beans on occasion. This phenomenon is addressed in some detail in the book “Genetic Improvement of Cacao”, edited by L.A.S Dias. The whole book is freely available online here:
Here’s a relevant passage from the book, taken from Chapter 3:
“Botanical expeditions, which collected cacao germplasm in the Brazilian Amazon region, confirmed the presence of white cotyledon cacao in natural Forastero populations of the Lower Amazon, in a higher frequency than expected [...]. Cacao trees with white seeds were also identified among the Bahia Forastero populations of the Lower Amazon and classified as mutants, designated ‘Almeida’ (Bondar, 1938b) and ‘Catongo’ (Miranda & Silva, 1939), increasing the complexity of the scenario even more.
Thus, Amazon Criollo and Forastero with white seeds could be classified as, initially, mutants preserved by man.”
Interestingly, Dias believes that all primitive cacao seeds were probably white. His reasoning is that the seeds of every other species within the Theobroma genus are white.
Dias surmises that at some time in pre-history, the change to purple seeds happened because that colouration conferred “some adaptive advantage” to the species. This fits in neatly with what we know about the protective properties of the purple antioxidants known as anthocyanins, which give Forastero beans (and other red, blue, and purple plant products) their distinctive colours.