Griffiths G. Atungulu

Continuous and pulsed ultrasound-assisted extractions of antioxidants from pomegranate peel

There is a great demand for developing efficient extraction methods in order to reduce extraction time and increase the yield and activity of functional antioxidants. The yields, activities, and extraction kinetics of antioxidants from the dry peel of pomegranate marc were studied using ultrasound-assisted extraction in continuous and pulsed modes and the results were compared with conventional extraction (CE) at a temperature of 25±2 °C and water/peel ratio of 50/1, w/w. The studied factors were intensity level and treatment time for continuous ultrasound-assisted extraction (CUAE), and intensity level, number of pulse repetition, and pulse duration and interval for pulsed ultrasound-assisted extraction (PUAE). The results showed that all factors significantly affected the antioxidant yield, but only treatment time had a significant effect on the antioxidant activity. Compared to CE, PUAE at an intensity level of 59.2 W/cm(2), and a pulse duration of 5s and a resting interval of 5s increased the antioxidant yield by 22% and reduced the extraction time by 87%. Similarly, CUAE at the same intensity level increased the antioxidant yield by 24% and reduced the extraction time by 90%. Since PUAE had 50% energy saving compared to CUAE, we recommend using PUAE for the extraction with antioxidant yield of 14.5% and DPPH scavenging activity of 5.8 g/g. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound-assisted extractions under PUAE and CUAE. This research clearly demonstrated the superiority of PUAE for producing antioxidants from peel of pomegranate marc.

INTEGRATED EXTRACTION AND ANAEROBIC DIGESTION PROCESS FOR RECOVERY OF NUTRACEUTICALS AND BIOGAS FROM POMEGRANATE MARC

Pomegranate marc (PM), a by-product of pomegranate juice processing, has not been effectively utilized. The objectives of this study were: (1) to determine the yields and properties of antioxidants (henceforth referring to total phenolics in terms of tannic acid equivalent) and oil extracted from various dry and wet constituents of PM, including peel, seeds, and mixture; and (2) to evaluate the anaerobic digestibility and biogas production potential of PM before and after antioxidant extraction (AE) and oil extraction (OE). Water and petroleum ether were used as solvents in the extraction of antioxidants and oil, respectively. The anaerobic digestion tests were conducted at 35°C ±2°C with a feedstock to microorganism ratio of 0.5 on volatile solid (VS) basis under two initial organic loadings of 3.0 and 5.0 g VS L -1 . According to the results, both dry and wet PM extracts had similar extraction efficiency and functionality. The wet PM extract had an antioxidant content of 23.0%, which corresponded to an antioxidant yield of 106 kg per ton of PM peel on dry basis (d.b.). The DPPH scavenging activities of antioxidants were 6.5 to 6.6 g g -1 (d.b.). The oil yield from the dry PM seeds was 138 kg ton -1 (d.b.). Compared to the low initial organic loading, the high initial organic loading improved methane content (55.1% to 67.5%) but not biogas yield. The extracted residuals of peel, seeds, and mixture had methane yields of 148, 183, and 161 mL g -1 VS, respectively, which were lower than that from raw PM. Because the integrated process of extraction followed by anaerobic digestion can produce high functional antioxidants and high-quality biogas and oil from the PM, it is recommended as a value-added utilization method for the by-product.

Technical Note: Development of Infrared Radiation Heating Method for Sustainable Tomato Peeling

Although lye peeling is the widely industrialized method for producing high quality peeled fruit and vegetable products, the peeling method has resulted in negative impacts by significantly exerting both environmental and economic pressure on the tomato processing industry due to its associated salinity issues and wastewater disposal problems. The objective of this research was to develop alternative peeling methods with reduced or no caustic usage to produce high quality peeled tomatoes. The feasibility of using infrared radiation (IR) peeling and lye-IR peeling as alternative technologies was evaluated against control treatment which used regular lye peeling alone. Peeling performance and peeled tomato quality of three tomato cultivars were determined. The metrics for peeling performance were peelability, peeling easiness, and peeling weight loss. The color and texture of peeled tomatoes were measured as quality indicators. The study showed that IR peeling resulted in a similar peeling easiness but yielded lower peeling loss and firmer peeled product for the same or slightly longer peeling time when compared to regular lye peeling method. Pretreatment with low concentration of lye solution prior to IR treatment did not show any advantages over IR peeling alone. Because IR dry-peeling produced high quality product without using water and salts, it is concluded that it has a good potential as an alternative peeling method to the regular lye peeling method.

Infrared heating for food and agricultural processing.

Fundamentals and Theory of Infrared Radiation Soojin Jun, Kathiravan Krishnamurthy, Joseph Irudayaraj, and Ali Demirci Infrared Radiative Properties of Food Materials Griffiths Gregory Atungulu and Zhongli Pan Heat and Mass Transfer Modeling of Infrared Radiation for Heating Fumihiko Tanaka and Toshitaka Uchino Emitters and Infrared Heating System Design Ipsita Das and S.K. Das Infrared Drying Caleb Nindo and Gikuru Mwithiga Combined Infrared and Hot Air Drying Habib Kocabiyik Combined Infrared Radiation and Freeze-Drying Griffiths Gregory Atungulu and Zhongli Pan Vacuum Infrared Drying Chatchai Nimmol and Sakamon Devahastin Infrared Dry Blanching Zhongli Pan and Griffiths Gregory Atungulu Infrared Baking and Roasting Servet Gulum Sumnu and Semin Ozge Ozkoc Infrared Radiation Heating for Food Safety Improvement Kathiravan Krishnamurthy, Soojin Jun, Joseph Irudayaraj, and Ali Demirci Industrial Applications of Infrared Radiation Heating and Economic Benefits in Food and Agricultural Processing Belgin S. Erdogdu, Ibrahim H. Ekiz, Ferruh Erdogdu, Griffiths Gregory Atungulu, and Zhongli Pan

Respiration and climacteric patterns of apples treated with continuous and intermittent direct current electric field

Abstract Negative corona discharge and parallel plate electrode configurations were used to investigate the efficacy of intermittent and continuous electric field treatment in retardation of respiration and suppression of climacteric peak in apples ( Malus domestica Borkh, c.v. Fuji, Sansa, Starking Delicious and Golden Delicious) post-harvest. Direct current electric field was generated by a 50 Hz alternating current supply. The electrodes were kept 8 cm apart. Climacteric peak CO 2 evolution in apples stored at 0, 10 and 23 °C were affected by high electric field treatment. Treatment of apples in high electric field suppressed CO 2 evolution at climacteric peak. Both treatments in a uniform field of parallel aluminum plate electrode and a negative corona discharge field retarded respiration in apples. Further, the direction of electric field using the parallel aluminum plate electrode influenced apple respiration.

Three-Dimensional Geometric Modeling of Processing Tomatoes

Characterizing tomato geometries would facilitate computer-based engineering simulation for processing optimization and equipment design. This research sought to develop a three-dimensional geometric model that can represent the morphological attributes of processing tomatoes of different masses and heights. A new tomato shape equation was derived as a function of radius in a polar coordinate system and includes the dimensional parameters and shape coefficients. To determine the unknown coefficients in the shape equation, an analytical relationship between tomato shape and size was deduced and then correlated to the distribution of tomato mass and height through linear regression analysis. A finite element meshing method was used to generate geometric models in three- and two-dimensional forms for describing the variability of size and shape. Validations of the three-dimensional model with experimentally measured values of tomato mass and surface area resulted in good precision and accuracy in terms of R2, RMSE, and RPE values. It is concluded that the developed equation and model are useful for quantifying a number of tomato geometric attributes, such as volume, surface area, radius of curvature, etc. Because the equation captures the important shape features of tomatoes with simple measurements, it is a practical and effective tool for many applications related to tomato processing and handling.

Use of an Electric Field to extend the Shelf Life of Apples

Abstract An effort was made to assess the effect of electric field treatment on the shelf life of Fuji, Rome Beauty, Golden Delicious and Starking Delicious apple varieties. The direct current electric field was generated by a 50xa0Hz alternating current supply. Ionisation by negative corona discharge was facilitated using needles as the cathode and an aluminium plate (of diameter 180xa0mm) as the grounded anode. The electrodes were 8xa0cm apart. Seven days continuous treatment with the electric field (generated by 10xa0kV) at 23°C air temperature and 75% relative humidity resulted in suppression of CO 2 evolution in the treated apples compared to control samples. Short treatment periods (1 and 2xa0h) at 10 and 20xa0kV reduced respiration in the apples. The total colour difference and soluble sugar concentration changes were lower in treated samples compared to control samples. Mechanical properties evaluated from the stress–strain relationship showed that the treated apple tissues were stiffer than the untreated ones.

Feasibility Study of Using Infrared Radiation Heating as a Sustainable Tomato Peeling Method

Lye peeling technique is putting both environmental and economic pressure on California tomato processing industry due to its associated salinity issues and wastewater disposal problems. This study is aimed at developing alternative peeling methods with reduced or no caustic usage to produce high quality peeled tomatoes. The studied five peeling methods were lye peeling, Infrared (IR) peeling, lye-IR peeling, enzymatic peeling and enzyme-IR peeling. Peeling performance and peeled tomato quality of three tomato cultivars were determined. The peeling performance was evaluated based upon peelability, peeling easiness, and peeling weight loss. The color and texture of peeled tomatoes were measured as quality indicators. The study showed that IR peeling resulted in a similar peeling easiness but yielded lower peeling loss and firmer peeled product compared to regular lye peeling method when IR peeling used the same or slightly longer time than lye peeling. Pretreatment with low concentration of lye or pectinase enzyme solution prior to IR treatment did not show any advantages over IR peeling alone. It is, therefore, concluded that IR-peeling has a good potential as an alternative to the current lye peeling method used in the tomato industry.

Separation Methods and Chemical and Nutritional Characteristics of Tomato Pomace

Tomato processing generates a large amount of pomace as a low-value by-product that is primarily used as livestock feed or disposed of. The objectives of this research were to investigate the chemical and nutritional characteristics and determine effective separation methods of the peel and seed of commercial tomato pomace from hot and cold break processes. The chemical composition of pomace, including fatty acid content of the seed oil, and the nutritional quality, including amino acid profile of defatted seed, were determined. The impacts of dry and wet separation on physicochemical properties of the peel and seed were evaluated. Based on the results, the studied pomace samples were rich in nutrients, including fat (8.37% to 16.24%), protein (15.08% to 22.70%), insoluble dietary fiber (IDF) (48.49% to 64.75%), soluble dietary fiber (SDF) (8.91% to 10.04%), and lycopene (98.16 to 172.07 mg kg-1). The seed oil had total unsaturated fatty acid content up to 80.10%, and the defatted tomato seed contained six kinds of essential amino acids, with histidine, an essential amino acid for infants, as the most dominant (23.34%). Both the dry and wet separation methods were effective for separation of the studied pomace. However, wet separation caused significant loss of micronutrients. The study indicated that commercial tomato pomace can be separated without water and used to produce value-added products with high nutrients.

Determination of Dockage for Accurate Rough Rice Quality Assessment

Abstract. Determination of dockage of freshly harvested rice is crucial for precise development of a universal rice shrink chart. The objectives of this research were to determine the effect of different factors, including rice variety, farm location, harvest moisture and time, drying, dropping, weather events such as wind and rainfall, and type of harvester, on dockage. The study was conducted during two consecutive rice harvesting seasons. The dockage of freshly harvested rice with moisture content (MC) ranging from 18% to 27% wet basis (w.b.) varied between 0.2% and 2.0% with averages of 0.92% and 0.79% in 2010 and 2011 harvest seasons, respectively. The corresponding averages of dockage of dried rice with MC of 14±1% (w.b.) were 0.78% and 0.65%, which were lower than those of freshly harvested rice. There were no significant differences (p>0.05) in dockage among the studied rice varieties. It was also observed that dockage was not significantly affected (p>0.05) by the harvest MC, geographical location and dropping from certain height. However, wind and rainfall events significantly (p