Question

The Andean Altiplano, a high-altitude plateau spanning parts of modern Bolivia and Peru, presents a notoriously harsh environment characterized by intense solar radiation, thin air, and extreme diurnal temperature fluctuations. To thrive in this arid landscape, the ancient Tiwanaku culture developed sophisticated agricultural and preservation techniques, most notably the production of chuño—a freeze-dried potato product that could be stored for years. The creation of chuño relied entirely on the region's unique microclimate. During the Andean winter nights, temperatures regularly plummeted below freezing, which crystallized the water content inside the harvested tubers. The subsequent daytime sun exposure, combined with the low atmospheric pressure of the Altiplano, allowed this frozen moisture to sublimate directly into vapor without returning to a liquid state. By bypassing the liquid phase, the potatoes were effectively dehydrated before rot-inducing bacteria could proliferate. Additionally, the physical trampling of the potatoes by Tiwanaku farmers during the transition between freezing and thawing cycles was crucial: this mechanical pressure ruptured the potato cell walls, forcing out remaining cellular liquids and preventing the formation of large ice crystals that would otherwise degrade the starch structures. Consequently, the resulting chuño retained its nutritional value and structural integrity, serving as a reliable safeguard against crop failures and seasonal famines.

Based on the passage, the degradation of the potatoes' starch structures during the production of chuño was prevented as a direct result of which of the following?