Changes in the chemical and nutritional composition of pinipig (rice flakes) during processing and storage.

Loss in moisture, protein, fat and ash was higher in puffed pinipig than when toasted. Loss in iron, calcium, phosphorus, thiamine, niacin and riboflavin followed the same trend but loss was higher in iron and thiamine content. Amylose also significantly decreased resulting the decrease in the amount of starch and concomitant increase in the amount of reducing sugar. B-carotene content which was initially high was totally destroyed in puffed pinipig. Slight changes in the chemical and nutritional composition were observed in pinipig samples packed in either aluminum pouch or laminate bag but higher values were obtained in pinipig samples packed in laminate bags. Moisture increased white fat, ash and protein content decreased. Fiber content remained unchanged. The onset of rancidity in samples packed in laminate bags was characterized by an increase in free fatty acids and acidity. Starch loss was also accompanied by a decrease in amylose content and an increase in reducing sugars. Losses in iron and thiamine content were also higher in samples packed in laminate bags. Pinipig samples in aluminum pouches were relatively stable over the three months of storage. Thus, it was a better packaging material because of its greater resistance to the entry of moisture and gases. Puffed pinipig was comparable in sensory attributes of a commercial rice flake product. Pinipig-based products like "bibingka", "suman", "kalamay" and "sinukmani" were also preferred over those prepared from either whole or ground rice. The retention of green color and the characteristic rice odor and flavor were the primary sensory attributes affecting their accpetability. The best pinipig was processed from the waxy rice.