Carolina Henríquez’s research while affiliated with University of Valparaíso and other places

Edible ingredients derived from phenolic bioactive enriched fruits such as apple can be integrated into food formulations to improve overall human health‐relevant functionalities. High phenolic bioactive enriched apple peels were used as a source of dehydrated edible ingredients for formulating cereal‐based muffin and apple puree. Prior to utilizing in food formulations, proximate composition, dietary fiber, mineral composition, and phenolic‐linked antioxidant activity of the source material, and apple peel dehydrated (APD) powder were evaluated. Furthermore, chemical composition, phenolic‐linked antioxidant, anti‐hyperglycemic properties (α‐amylase and α‐glucosidase enzyme inhibitory activities), and sensory properties of the formulated food, muffin, and apple puree, with and without APD powder integration were determined. Total phenolic content, dietary fiber content, total antioxidant activity, and anti‐hyperglycemic properties increased with the incorporation of APD powder, specifically in muffin. These results suggested that the APD powder can be rationally utilized as edible ingredients to improve overall nutritional qualities, especially for type 2 diabetes‐linked benefits. The practical application of this study is to optimize the processing strategy (selection of the anti‐browning agent and hot air drying process) for improving the stability and retention of human health‐promoting phenolic bioactives and associated antioxidant and anti‐hyperglycemic functionalities in apple peel dehydrated (APD) powder. Additionally, phenolic bioactive enriched APD was integrated as high‐value edible ingredients in common cereal‐based food formulation (muffin) and apple puree to improve overall type 2 diabetes‐relevant benefits linked with anti‐hyperglycemic and antioxidant properties. This innovation can be advanced to design novel cereal‐based food formulations by integrating phenolic bioactive enriched edible ingredients derived from fruits and vegetables for improved nutritional and health benefits targeting dietary prevention and management of non‐communicable chronic diseases, such as type 2 diabetes.

Pine nut (Pinus pinea L.) is a nutritious, expensive tree nut. During storage, it is exposed to a wide range of environmental deteriorative conditions. This study describes the oxidative stability of pine nuts kept in pouches made of three different packaging materials and stored at three different temperatures. The packaging materials evaluated were low-density polyethylene (LDP), high-density polyethylene (HDP), and high-barrier metallized film (MF). Temperatures evaluated were 4, 20, and 60°C. In addition, a control unpacked sample was also evaluated in identical conditions. The oxidative parameters evaluated were acid value and peroxide value. Data analyses include a shelf-life study and a principal component analysis. The results obtained indicate what the best packaging material at 20°C was MF with a shelf-life of 703 d. At 4°C, the shelf-life of pine nuts stored in HDP was 1148 d. It is concluded that it is fundamental to use an adequate packaging to protect the seeds from environmental conditions that promote deterioration.

The Chilean National School Feeding Program (NSFP) delivers breakfast and lunch meals that supply 250 and 450 kcal, respectively, along the country. In the last decades, a significant increase of obesity has been observed in primary education children, and it involves risk factors of non-communicable diseases. The dietary intake of foods containing phenolic compounds (PC) exerts favorable effects on health by reducing risk factors of prevalent diseases. The aim of the study was to measure the PC content and antioxidant capacity (AC) [ORAC and DPPH] of meals provided by the NSFP in Quillota, Chile, in 2011. The PC supply of the whole meals served ranged from 362.7 to 1,730 mg GAE. The best breakfast foods include whole grain cookie (2.59±0.3 mg GAE/g), bread with avocado, quince jelly or strawberry jam (1.61±0.13 to 2.05±0.3 mg GAE/g); while the best lunch salads include beetroot, lettuce, and cabbage/fish (1.66±0.3 to 2.35±0.1 mg GAE/g), and main courses contain legumes, or mixed vegetables. The lowest PC contents were observed in pasta and rice preparations (p<0.05). Among desserts, the best source of PC is fruit (1.81±0.04 to 6.91±0.31 mg GAE/g). The correlation between PC and AC varied according to the type of meal. PC content and AC are additional criteria for selecting the best quality meals, in addition to the nutrients and energy content. The results support the recommendation to increase the supply of fruits and vegetable/legumes preparations and fruits instead of starchy foods to scholars

The study evaluated the impact of dehydration on the total phenolic content (TPC) and antioxidant capacity (AC) of fruits and vegetables (F&V). Fresh small fruits (berries) had the highest TPC, anthocyanin contents, and AC (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC)). The lowest TPC were observed in carrot and tomato and the lowest anthocyanins were observed in fresh sweet peppers (green and red), red apple, carrot, and tomato. Dehydrated blackberry and eggplant exhibited the highest TPC and anthocyanins. The retention of phenolics after drying ranged from 38.5% (spinach) to 92.1% (red apple). TPC increased in dehydrated tomato and green apple. The lowest DPPH and ORAC were obtained in dried carrot and tomato. DPPH retention ranged from 16.4% (tomato) to 64.7% (blackberry). Dehydrated small fruits and sweet peppers presented lower AC (ORAC) retention, while most dehydrated F&V increased ORAC, ranging from 9.5% (carrot) to 52.9% (eggplant). Dehydrated F&V represent good quality functional foods or ingredients.

The apple peel, a by-product of apple processing, has a high total phenolic content (TPC); however, these compounds can be highly thermosensitive and unstable. Therefore, the aim of this study was to determine the degradation kinetics of the TPC in apple peels during drum-drying as a stabilization and recovery method. Apple peels (Granny Smith) were dried at 110, 120, 130 or 140 °C for 250 s with a constant drum clearance (0.2 mm). TPC degradation exhibited first-order kinetics and their retentions at the end of the process were 73.13% at 110 °C, 57.28% at 120 °C, 43.40% at 130 °C and 21.10% at 140 °C. Finally, empirical models were significantly fitted to predict the TPC as the apple peels reached a certain level of dehydration, which may be useful from the processing standpoint and validate the use of drum-drying as a process tool for the recovery of apple industrial wastes.

The bioavailability of major phenolics in Autumn Royal grape juice was measured in 16 subjects distributed into two groups: the experimental group (n = 8 receiving 300 mL of juice) and the placebo group (n = 8 receiving 300 mL of artificial beverage). Blood was obtained before and after 30, 90, 180, and 300 min after juice or placebo intake and 24-h urine was collected. At 30 min, catechin and gallic acid levels were 3.18 ± 0.06 and 0.33 ± 0.06 nmol/mL plasma (p < 0.01), respectively. The maximal plasma levels of catechin and gallic acid observed at 180 min were 7.11 ± 0.53 and 1.56 ± 0.07 nmol/mL, respectively. After 300 min, gallic acid was not detected and only two subjects exhibited measurable levels of catechin. After juice intake, urinary catechin and gallic acid contents were significantly higher than the basal values (p < 0.001). After a regular serving of grape juice, catechin and gallic acid are bioavailable and thus potentially capable of exerting their expected biological effects.

Apples have been identified as one of the main dietary sources of antioxidants, namely phenolic compounds. Apple peel constitutes a waste of dried apple manufacture, although it contains more phenolics than the fruit pulp. This fraction can be preserved by drying. However, it is important to consider that the dehydrated product obtained requires protection. The objective of this research was to study the stability of drum dried apple peel powder in order to select the suitable packing material: high-density polyethylene (HDPE) or metalized films of high barrier (MFHB). The samples were stored under accelerated (38 °C, 90% RH) and conventional (25, 10 and 4 °C, 60–70% RH) conditions during 120 days. Kinetic modelings for the attributes degradation were evaluated. Total phenolics and moisture levels are largely dependent on the type of packing and storage conditions. The apple peel powder samples packed in MFHB pouches preserved most of the phenolic compounds, and exhibited lesser moisture increase. In addition, the shelf-life was higher in the samples packed in MFHB: 298 ± 18.41 days vs. 120 ± 4.59 days under conventional and accelerated conditions, respectively.

Grapes (Vitis vinifera L.) are a source of phenolics and exhibit a high antioxidant capacity. In this study, the total phenolics content and the antioxidant capacity of ground grapes, juice, and skin fractions of two varieties of red grapes widely produced in Chile (Cabernet Sauvignon and País) were analyzed and specific phenolics (caffeic acid, gallic acid, resveratrol and catechin) were determined. The total phenolics content and antioxidant capacity were higher in Cabernet Sauvignon grapes vs. País, mainly in the skin fraction. The predominant phenolic species in all grape fractions was catechin, except in the skin of Cabernet Sauvignon, where resveratrol prevailed. Phenolic acids were not detected in grape juices, probably due to the absence of skin. Significant high correlations between specific phenolics, total phenolics content and antioxidant capacity were observed. The study presents practical data on some relevant chemical characteristics of grape fractions that are associated to potential health benefits.

We hypothesize that the Ferric Reducing Antioxidant Power (FRAP) assay that follows the reaction of Fe(3+)-TPTZ at 593 nm underestimates the antioxidant capacity of fruits, since the standardized time of the reaction (4 min) is not enough to titrate all the reducing compounds available. We measured FRAP, total phenolics and anthocyanins content in a variety of Chilean berry fruits (blueberries, blackberries, raspberries and strawberries) and apples (cv. Fuji, Granny Smith, Pink Lady, Red Delicious and Royal Gala). Taking into account the dependence of FRAP on the time course of the reaction, we propose to measure FRAP indexes after 1 min (FRAP-1), 30 min (FRAP-30) and 120 min (FRAP-120) of incubation. Most fruit extracts showed significant correlations between the antioxidant capacity and the incubation time, although in some cases the FRAP indexes did not correlate with the total phenolics and/or anthocyanins content. In fact, in apples and berries the correlation between anthocyanins content and FRAP indexes decreased with the incubation time. It is concluded that the fruit extracts analyzed require an incubation period higher than the established in the original experimental protocol to reach the equilibrium, due to the presence of a complex mixture of antioxidant compounds. In addition, a kinetic profile should be realized in each sample studied to establish the most suitable incubation period to titrate all the reactive antioxidant species.