Conceptual Physics (12th Edition)

Each gram of water that that freezes releases 80 calories of energy to the fruit and the air nearby (page 330, Figure 17.18). This energy helps keep the temperature above $0^{\circ}C$. The fruit contains sugary water, which lowers its freezing point below $0^{\circ}C$ (page 327). Furthermore, the ice layer acts as a custom-fitted insulating blanket, protecting the fruit against heat loss.