ABSTRACT: IN THIS STUDY, THE EFFECTS OF THE AMYLOSE/AMYLOPECTIN CONTENT ON STARCH GELATION AND THE PHYSICAL CHARACTERISTICS OF HYDROGELS PRODUCED BY HPP WERE STUDIED BY OPTICAL AND RHEOLOGICAL MEASUREMENTS IN STEADY-STATE CONDITIONS. ADDITIONALLY, THE EFFECTS OF THE STORAGE TEMPERATURE (4 ?C AND 20 ?C) AND TYPE OF PACKAGING (PLASTIC BAGS OR SEALED PETRI DISHES) ON THE PHYSICAL STABILITY OF THE HYDROGELS WERE EVALUATED FOR 30 DAYS OF STORAGE BY EVALUATING THE SHRINKAGE OF THE GRANULES, AS WELL AS THE WEIGHT LOSS, WATER ACTIVITY, ORGANOLEPTIC, AND RHEOLOGICAL PROPERTIES. THE EXPERIMENTAL FINDINGS SUGGESTED THAT AMYLOSE PLAYS AN ANTAGONISTIC ROLE IN DETERMINING THE CAPACITY OF THE STARCH GRANULES TO ABSORB WATER UNDER PRESSURE AND TO CREATE STABLE AND STRUCTURED GELS AND ON THE PHYSICAL STABILITY OF HYDROGELS DUE TO ITS INFLUENCE OVER THE STARCH RETROGRADATION EXTENT DURING STORAGE. TWENTY PER CENT AMYLOSE WAS THE MINIMUM CONCENTRATION TO FORM STABLE CORN STARCH HPP HYDROGELS WITH GOOD PHYSICAL AND RHEOLOGICAL PROPERTIES. MOREOVER, A STORAGE TEMPERATURE OF 20 ?C AND THE USE OF POLYMERIC BAGS WERE EVALUATED AS THE MOST SUITABLE STORAGE CONDITIONS AND PACKAGING MATERIALS ENABLING THE LONG STORAGE OF CORN STARCH HYDROGELS.

THE DEVELOPMENT OF NATURAL SYSTEMS SUCH AS STARCH-BASED BIOPOLYMERS AND THEIR APPLICABILITY PRESENT A SUBSTANTIAL CHALLENGE TO THE FOOD INDUSTRY, UNDERSCORING THE CRITICAL NEED TO EXTEND THE INVESTIGATION TO THEIR DIGESTIBILITY. THIS STUDY INVESTIGATED THE IN VITRO DIGESTIBILITY OF RICE AND TAPIOCA STARCH-BASED HYDROGELS, OBTAINED BY HIGH-PRESSURE PROCESSING (HPP) (600 MPA FOR 15 MIN) AND BY CONVENTIONAL THERMAL TREATMENT (80 °C FOR 15 MIN) TO ASSESS THE INFLUENCE OF HPP ON STARCH DIGESTIBILITY AS WELL AS TO IDENTIFY THE CRITICAL DIGESTION STEPS. DURING IN VITRO DIGESTION, DISINTEGRATION, TOTAL HYDROLYSED STARCH, AND STARCH NUTRITIONAL FRACTIONS WERE DETERMINED. RESULTS DEMONSTRATED THAT RICE HYDROGELS UNDERWENT A HIGHER DISINTEGRATION EXTENT AND DEGREE OF STARCH HYDROLYSIS WITH RESPECT TO TAPIOCA HYDROGELS, BEING THIS MORE EVIDENT IN HPP HYDROGELS. BOTH HYDROGELS WERE ALMOST COMPLETELY DIGESTED AT THE END OF THE DIGESTION PHASES, WITH HYDROLYSED STARCH HIGHER THAN 94% AND 88% FOR RICE AND TAPIOCA, RESPECTIVELY. HPP COULD REPRESENT A KEY TECHNOLOGY TO INCREASE THE DIGESTIBILITY OF THE RESISTANT STARCH FRACTION OF RICE AND TAPIOCA STARCH HYDROGELS, INCREASING THE POTENTIAL APPLICABILITY OF THESE BIOPOLYMERS.

THIS STUDY AIMED TO INVESTIGATE THE EFFECTS OF SEMOLINA CHARACTERISTICS AND PASTA-MAKING PROCESSING ON THE QUALITY OF DURUM WHEAT SPAGHETTI (A, B, AND C) USING A REVERSE ENGINEERING APPROACH. METHODS: PROXIMATE COMPOSITION, COLOR, GRANULOMETRY, PASTING AND THERMAL PROPERTIES WERE DETERMINED TO CHARACTERIZE SEMOLINA, WHILE PASTING, THERMAL AND COOKING PROPERTIES, MICROSTRUCTURE AND SENSORY PROFILE WERE EVALUATED FOR SPAGHETTI.

THE AIM OF THIS STUDY WAS TO EVALUATE THE EFFECT OF HHP AND RIGOR STATE ON PALM RUFF (SERIOLELLA VIOLACEA) MUSCLE PROTEINS. HHP TREATMENTS WERE PERFORMED AT 450?550 MPA FOR 3 AND 4 MIN AT 15 °C. PROTEIN SECONDARY STRUCTURE WAS EVALUATED BY USING FOURIER TRANSFORM INFRARED SPECTROSCOPY, AND THE THERMAL BEHAVIOR WAS EVALUATED BY USING DIFFERENTIAL SCANNING CALORIMETRY. THE RESULTS SHOWED THAT HHP TREATMENTS REDUCED ?-HELIX AND INCREASED ?-SHEET IN FISH PROTEIN STRUCTURES. THROUGHOUT THE 35-D STORAGE PERIOD, SECONDARY STRUCTURES IN HHP SAMPLES CHANGED DEPENDING ON PRESSURE INTENSITY, HOLDING TIME, AND RIGOR STATE. THE THERMOGRAMS OF PALM RUFF MUSCLES SHOWED FOUR ENDOTHERMIC TRANSITIONS IN PRERIGOR STATE AND THREE IN POSTRIGOR STATE. THE HHP TREATMENT AFFECTED THERMAL STABILITY OF MYOSIN PROTEIN, WHICH IS REFLECTED IN THE CHANGE OF DENATURATION TEMPERATURE (T D) AND A DECREASE IN DENATURATION ENTHALPY (?H D) WITH RESPECT TO THE NATIVE PROTEIN; ACTIN WAS DENATURED BY THE PRESSURE TREATMENTS. IN CONCLUSION, RIGOR STATE AND HHP AFFECTED PROTEIN STRUCTURE OF FISH PROTEINS.