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Abstract. Apricot (Prunus armeniaca) is a stone fruit commonly consumed in sun-dried form. Processors often apply a sulfite pretreatment to the fruit to help maintain its vivid orange color and nutrient content during drying. However, there is a population that is sensitive to sulfites, and organic dried fruit cannot contain sulfites. Thus, next-generation solar drying systems are needed to help reduce or eliminate sulfites via improved processing conditions. In this work, 2 types of acrylic dryer lid (standard clear and UV-blocking) were compared to open-air drying to determine their effects on degradation of several nutrients of interest in apricots. In addition, pretreatments of 25-minute sodium metabisulfite dips at 1 of 3 levels (High – 60 ppm, Medium – 15 ppm, Low – water dip) were applied to the apricots to determine effects from sulfite pretreatment intensity. Three replicate sun-drying runs were performed at the USDA – Agricultural Research Service laboratory in Albany, California, during the Fall of 2017. Results showed that nutrients of interest decreased significantly over time for all treatments. The UV-Blocking acrylic yielded higher residual sulfites than did the open-air treatment. Sulfite treatment had a significant effect on total soluble phenolics and antioxidant activity, with the High sulfite treatment yielding the lowest values of these quality metrics. Vitamin C was higher in High sulfite pretreatment than Medium or Low. β-carotene content increased with increasing intensity of sulfite pretreatment. The results of this work will inform the design of solar drying systems for both sulfited and unsulfited apricots.