Three varieties of native potato (Imilla blanca, Imilla negra and Loc'ka) that grow in the Andean region at more than 3800 m.a.s.l. were selected fot the extraction and characterization or their starch. Instrumental techniques such as scanning electron microsocopic (SEM), differential scanning calorimetry (DSC), Fourier transformed infrarred spectroscopy (FTIR), X-ray diffraction, colorimetry and polarized light microscopy were used. The results showed that only Loc'kás starch had a unimodal granule size distribution, whereas Imilla negra and Imilla blanca starches showed two and three granule size populations, respectively. The starch from Imilla negra showed higher apparent amylose content, peak viscosity, phosphorous content and paste clarity. The starch from Imilla blanca showed high relative crystallinity, while Imilla blanca and Imilla negra had higher intensity ratios than that from Loc'ka, suggesting high molecular order. Cooked starch from Imilla negra showed higher resistant starch (RS) fraction than the other starches studied.

The potato (Solanum tuberosum) is an important source of starch which is underused in Peru, as are mainly imported potato starch, for has not been achieved yet, industrialization starch extraction is a success. This study aimed to obtain, characterize and modify chemically by acetylation, starch of a commercial potato variety, Unique. Extraction was performed with water and chemical modification was performed by acetylation using acetic anhydride at different levels (% v/w starch): 5, 10 y 15%. Native starch and modified starch were characterized: proximate composition, clear gel, apparent viscosity and stability to the freeze, also the percentage of acetyl groups (GA) was measured. The extraction yield was 16.5% and the apparent viscosity of native potato starch was 25000 mPas. Also starch modified with 15% acetylation for application in a cream ice cream because of their functional characteristics was selected. The apparent viscosity of gels modified starch potato was 5429 mPas. Acetyl groups varied from 0.44 to 1.26 % and degrees of substitution did not exceed levels recommended by FAO and JECFA. Starch AAc 15% showed the best functional profile for its application as stabilizer and thickener in refrigerated foods.

There are many varieties of native potatoes grown in different regions of Peru, usually for farmers´ consumption. However, the possibility of a commercial use has led this work in order to give them added value. To evaluate the possibility of use of native starch from these potatoes, as an ingredient in the food industry, it was presented as objective to determine the physicochemical, functional and viscoelastic native potato starches obtained from Pampacorral properties (Cuzco, Peru): Puka Ambrosio (PA), Combe (CO), Perwanita (PER), Kalis qero (KQ), Qello virondos (QEV), Yana churos (YACH), Pitikiña (PI), Yana kusi (YAKU) y Solischa (SOL). For this purpose, slurries were prepared from native starch by heating until gelatinization. Moisture sorption, swelling and solubility showed were correlated with temperature increment. At 90 °C, PI starch showed greater values for swelling power (28.47%), water binding capacity index (22.70) and solubility (20.24%). Syneresis values, at 4 °C, were the lowest for CO and YACH starches, 3.8 and 4.6; respectively. All native potato starch gels showed pseudoplastic behavior (n G”) for varieties tested.