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50: Vacuum-frying Processing Technology Improves Quality Attributes of Fried Sweetpotato Chips



Vacuum-frying Processing

Technology Improves Quality

Attributes of Fried Sweetpotato Chips

O.P. Sobukola,* T.A. Esan, H.A. Bakare and L.O. Sanni

Federal University of Agriculture, Abeokuta, Nigeria


Sweetpotato (Ipomea batatas) is a very important crop in developing countries. Orange-fleshed varieties provide beta-carotene, a key antioxidant and source of provitamin A. However, sweetpotato does not store for a long period unless properly cured; hence the need for processing into shelf-stable forms such as fried snacks. This study investigated the effect of sweetpotato cultivars (EX-OYUNGA, 440216 and SPK 004), type of frying oil (groundnut oil, refined, bleached and deodorized oil (RBDO) and palm oil) and vacuum frying conditions (temperature – 108°C, 122°C and 136°C, vacuum pressure – 6.54 kPa, 13.21 kPa and 19.88 kPa and time – 3 min, 6 min and 9 min) on some quality attributes of fried sweetpotato chips. The response surface methodology technique based on the Box-Behnken design was used to optimize vacuum frying processes and study the effects of the variables on quality of fried chips. Twenty-eight combinations including five replicates of centre points were performed in random order. Seven responses such as oil and moisture content, beta-carotene, texture, lightness, redness and yellowness were considered to evaluate effects of independent variables on sweetpotato chips. Fried sweetpotato chips from optimized vacuum frying conditions were compared with atmospheric fried samples using the concept of equivalent thermal driving force (ETDF). Significant differences (P < 0.05) were observed among sweetpotato varieties and frying oil type. EX-OYUNGA and groundnut oil produced chips with acceptable quality attributes. Frying temperature and time as well as vacuum pressure have significant effect on beta-carotene, texture, lightness, redness and yellowness with coefficient of determination (R2) of models for responses investigated varying between 0.7179 and 0.951. The optimized coded vacuum frying conditions for the adopted cultivar (EX-OYUNGA) and frying oil (groundnut oil) were −0.64, 1 and −1 for frying temperature, vacuum pressure and frying time, respectively, based on the desirability concept of 0838. This choice was based on fried chips of lower oil and moisture contents, higher level of beta-carotene retention, lower breaking force, lighter and intense yellow colouration. When the optimized vacuum fried samples were compared with atmospherically fried ones, the former retained about 35% beta-carotene, had improved texture, were lighter and had a more intense golden yellow colour. Hence, vacuum frying could be an alternative for producing more nutritious deep-fat fried sweetpotato chips compared with atmospheric fried samples, the dominant current practice.

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8 The Light Spread of Time

John Sallis Indiana University Press ePub





The day is exquisite as it spreads its light over the entire valley. The scattered clouds are as brilliantly white as the sky is intensely blue. From this brilliance and intensity along with the sharpness with which the clouds are outlined against the sky, it can be seen that the air, at this moment, is exceptionally transparent, utterly diaphanous. The phenomenon is remarkable: the transparent air can, in this sense, be seen – directly, not by way of inference – even though it is not itself seen, not seen as such. It appears precisely in remaining the invisible, perfect medium of another appearing. It comes to light, not by reflecting light, as do things, but by giving free passage to light. Visibility, it appears, is not limited to visible things but can be bestowed on something invisible in and of itself, indeed in such a way that precisely its invisibility is what comes to light.

The clouds drift slowly along, their shapes gradually transforming as they become more airy and expansive or contract into denser forms, also as they extend wispy appendages toward other forms, some slowly merging, some separating into new shapes, in a play of resolution and dissolution that contests the very category of individuality. Nothing illustrates more concretely and immaculately the sense of drift than this light, airy show of forms. The play requires for its stage only the absolutely immobile diurnal sky. Yet the uniformity of the sky prevents it from providing a measure for the movement; it merely forms the expanse on which the drifting clouds can be observed in relation to each other.

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Medium 9781780647845

5 Propagation and Nursery Certification

Khan, M.M.; Al-Yahyai, R.; Al-Said, F. CABI PDF


Propagation and Nursery Certification

Muhammad Azher Nawaz1,2*, Yong-Zhong Liu1,

M. Mumtaz Khan3 and Waqar Ahmed4


College of Horticulture and Forestry Sciences, Huazhong Agricultural University/

Key Laboratory of Horticultural Plant Biology, Ministry of Education, Wuhan, China;


Department of Horticulture, University College of Agriculture, University of

Sargodha, Sargodha, Pakistan; 3Department of Crop Sciences, College of Agriculture and Marine Science, Sultan Qaboos University, Al-khod, Sultanate of Oman;


Sector Advisor-Horticulture, USAID-CNFA, Lahore, Pakistan


Propagation Methods

Plant propagation is the reproduction, duplication or multiplication of plants from the parent plant. The prime objective of the propagation is to produce more plants exactly like the parent plant. It is performed to save the germplasm, as well as for crop production on a commercial scale. Orchard establishment is a long-term investment and it has lifelong financial impacts. The availability of true to type certified, healthy and disease-free nursery plants leads to the success of an orchard.

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Medium 9781780643083

5: Managing the Team

Crafer, K CABI PDF


Managing the Team

The success of many start-up businesses in the early years is due to the entrepreneurial ability of the individual. Growth in the next phase of development is sometimes stunted because even though the founder is good at exploiting new ideas, they are less able to manage a team and help others reach their full potential. Often the skills that enabled the business to become a success in the early phase can be a barrier to future growth.

A study at the University of Cambridge (Hughes, 1998) looked at a real-time comparison of small- and medium-sized enterprises as they developed in international markets over 10 years. It was discovered that those businesses that stalled or faltered in their growth, when compared to those in the study with steady growth, were characterized by:

ill-defined strategic direction with regard to product and market development; poorly specified (or frequently changed) managerial responsibilities; inadequate devolution of managerial tasks and hence over-burdening of directors who may or may not hold the positions they do by design; and inadequately supported or poorly implemented management training programmes and management information systems.

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2 Geologic Overview

Edited by Alan L Titus and Mark A Loew Indiana University Press ePub

Alan L. Titus, Eric M. Roberts, and L. Barry Albright III

Cretaceous Strata in Southern Utah were Deposited in the proximal portion of the Sevier Foreland Basin. Total thickness of Cretaceous sediments probably exceeded 3000 m in the region before mid-Laramide uplift and erosion. Exposures are primarily found at the Kaiparowits Plateau and around the margins of the Markagunt and Paunsaugunt plateaus and the Pine Valley Mountain region. The Cretaceous section is divided up into the Cedar Mountain, Dakota, Tropic, Straight Cliffs, Wahweap, and Kaiparowits formations east of Parowan Canyon and is contained almost entirely within the Iron Springs Formation west. The sections are highly fossiliferous and yield one of the best records of Late Cretaceous terrestrial ecosystem evolution known in North America.

The state of Utah lies within both the Cordilleran Thrust Belt and Cordilleran Foreland Basin System (Fig. 2.1). The boundary between these two provinces, called the Cordilleran or Wasatch Hingeline (DeCelles, 2004), roughly parallels the east margin of the Sevier Fold and Thrust Belt. West of the Wasatch Hingeline are the extended and dissected remnants of thrust sheet stacks of Precambrian through early Mesozoic sedimentary rocks. East of the Wasatch Hingeline are thick sections of largely flat-lying Paleozoic, Mesozoic, and Paleogene sedimentary rocks (Hintze, 1988). Cretaceous strata crop out widely east of the Wasatch Hingeline, especially in the eastern Wasatch Plateau, Book Cliffs, Henry Basin, La Sal-Abajo Mountains, and the southern portion of the state (Fig. 2.2).

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