Blackcurrant, blueberry, and muscadine grape juices were efficiently sorbed, concentrated, and stabilized into dry granular ingredient matrices which combined anti-inflammatory and antioxidant fruit polyphenols with sweet potato functional constituents (carotenoids, vitamins, polyphenols, fibers). Total phenolics were highest in blackcurrant-orange sweet potato ingredient matrices (34.03 mg/g), and lowest in muscadine grape-yellow sweet potato matrices (10.56 mg/g). Similarly, anthocyanins were most concentrated in blackcurrant-fortified orange and yellow sweet potato matrices (5.40 and 6.54 mg/g, respectively). Alternatively, other protein-rich edible matrices (defatted soy flour, light roasted peanut flour, and rice protein concentrate) efficiently captured polyphenols (6.09–9.46 mg/g) and anthocyanins (0.77–1.27 mg/g) from purple-fleshed sweet potato juice, with comparable efficiency. Antioxidant activity correlated well with total phenolic content. All formulated ingredient matrices stabilized and preserved polyphenols for up to 24 weeks, even when stored at 37°C. Complexation with juice-derived polyphenols did not significantly alter protein or carbohydrate profiles of the matrices. Sensory evaluation of the ingredient matrices suggested potential uses for a wide range of functional food products.
With high phytochemical and starch contents, purple‐fleshed sweetpotatoes (PFSP) have been processed into various functional ingredients and food products including juices and natural colorants. For juice processing, PFSP are usually subjected to heat treatment for inactivation of pigment‐degrading enzymes. However, heating of sweetpotatoes gelatinizes starch and produces thick slurry with cooked flavor, which are the drawbacks. Development of alternative processes to overcome the stated problems will be beneficial to sweetpotato processors. This study demonstrated that acidified water (≥3% w/v citric acid) was effective in inhibiting polyphenol oxidase and peroxidase in raw PFSP resulting in an attractive reddish juice. About 93% total phenolics (TP) and 83% total monomeric anthocyanins (TMA) in PFSP were extracted by two repeated extractions. The combined PFSP juice (3.2 L/kg PFSP) had high levels of TP (1,850 mg/L) and TMA (475 mg/L). With the developed process, 167 g dried starch, and 140 g dried high‐fiber pomace were obtained for each kg raw PFSP, besides the highly pigmented juice. Pasteurization of the PFSP juice samples (pH 3.2) at 80 °C for 12 s resulted in 15% loss in TMA and had no effect on TP. The results indicated an efficient process to produce sweetpotato juice with high bioactive compounds and recovery of starch and high dietary fiber pomace as co‐products. Practical Application Purple‐fleshed sweetpotatoes (PFSP) are rich in polyphenolics and antioxidant activities. In PFSP juice extraction, heat treatment to inactivate the pigment‐degrading enzymes results in starch gelatinization and cooked flavor. A nonthermal process using acidified water was developed for producing anthocyanin‐rich juice from PFSP and concurrently recovering native starch and dried pomace, which would increase the economic feasibility of the developed process. The results demonstrate an efficient process for the sweetpotato industry in producing PFSP pigmented juice and co‐products for various food applications.
Background: The objective multiple-choice test is an assessment method that has been applied widely in universities. The meticulous judgment of complication and differentiation level of objective test questionnaire can beneficially lead to the growth of high quality multiple-choice questionnaire bank and effective examination. Objectives: To evaluate the difficulty level and differentiate level of the objective multiple-choice tests. Materials and method: The multiple-choice theory test (01 Elemental medical exam with 242 students, 01 Clinical medicine exam with 163 students). The difficulty degree of questions was determined by calculating the percentage of students who gave the answers correctly for the given questions in total. The differentiation level was differentiated by the percentage of students who answered correctly in corresponding groups: excellent, good, average, below average, poor. Results: The elemental medical examination comprises 7 hard questions, 58 medium questions, and 35 simple questions; 10 questions have poor degree of difference, 83 questions have good and very good degree of difference. The clinical medicine examination comprises 9 hard questions, 57 medium questions and, 34 simple questions; 23 questions have poor degree of differentiation, 51 questions have good and very good degree of difference. Conclusions: It is crucial to evaluate the difficulty and differentiation standards of the objective multiple-choice examination which enhance the quality of assessment. Thereby, the faculties need to regularly judge these factors while creating the questionnaire and completely evaluating the tests, and the inappropriate questions will be eliminated. Keywords: difficulty level, differentiation level, Objective multiple-choice test.
Boosting machining quality is a prominent solution to save production costs for burnishing operations. In this work, a machining condition-based optimization has been performed to decrease surface roughness (SR) and enhance Vickers hardness (VH) of the minimum quantity lubrication-assisted burnishing operation (MQLABO). The burnishing factors are the spindle speed (S), depth of penetration (D), and the air pressure (P). The burnishing trails of the hardened material labeled 40X have been conducted on a milling machine. The adaptive neuro-based-fuzzy inference system (ANFIS) was used to construct the correlations between the process inputs and MQLABO responses. The non-dominated sorting genetic algorithm-II (NSGA-II) is utilized to determine the optimal parameters. The scientific outcomes revealed that the optimal values of the S, D, and P are 800 RPM, 0.09 mm, and 4.0 Bar, respectively. The SR is decreased by 53.8%, while the VH is enhanced by 3.1%, respectively, as coBarred to the initial values.
Consumer demands for convenient, healthy foods have increased in recent years. Apples, peaches, and pineapples are high in bioactive compounds and may have anti‐cancer and anti‐diabetic effects. Common thermal processing techniques result in poor product quality and destruction of phytonutrients. Continuous flow microwave technology can process homogeneous and multiple‐phase foods and maintain high nutrient retention. This study aimed to quantify the effects of microwave processing on nutrient retention in fruit purees containing apple, peach, and pineapple. Different formulations of the fruits were pureed and filled in plastic, single serve cups and heated in a 2450 MHz household microwave oven at 100 ºC for 1, 2, and 3 minutes, a more rigorous process than pasteurization. Purees were extracted with acidified methanol and analyzed for total phenolics (TP) and antioxidant activity (AA) using Folin‐Ciocalteu and ORAC method, respectively. Vitamin C (VC) was extracted with 3% metaphosphoric acid, 8% acetic acid in water and analyzed on HPLC. There were no significant losses in any of the nutrients after microwave processing. With increased processing time, fruit cocktail processed for 3 min showed no significant losses in VC or AA and a significant increase in TP. These results demonstrate that microwave processing of fruit purees retains phytonutrients and may enhance their extraction from the fruit matrix.
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