Ground Apple Research Articles

Optimization of pre-drying treatment and drying mode for reducing browning to produce shelf stable fructooligosaccharide rich yacon (Ground Apple) powder

Optimization of pre-drying treatment and drying mode for reducing browning to produce shelf stable fructooligosaccharide rich yacon (Ground Apple) powder

The Effects of Added Water and Grinding Temperature on Stability and Degradation Kinetics of Antioxidant Activity, Phenolic Compounds, and Ascorbic Acid in Ground Apples.

The effects of added water (1:0 up to 1:4 apple:water w/v) and grinding temperature on browning and antioxidant capacity of apples were investigated. Grinding apple with addition of water decreased browning and loss of antioxidant activity when ground with water up to 1:3 ratio. Browning, antioxidant capacity, major phenolic compounds (chlorogenic acid, epicatechin, and procyanidin B2), and ascorbic acid in ground apple with water (1:1) were evaluated at grinding temperatures from 5 °C to 45 °C. The degradation of antioxidant activity, phenolic compounds, and ascorbic acid followed first-order kinetics. The temperature-dependent degradation was adequately modeled using the Arrhenius equation, and kinetic parameters such as k, t1/2 , Q10 , and Ea indicated that the grinding temperature was a key factor affecting retention of antioxidant activity, phenolics, and ascorbic acid contents in apple. PRACTICAL APPLICATION: The phenolic compounds and antioxidant activity of fruits and vegetables can be altered by processing such as thermal treatments and grinding. Therefore, it is important to evaluate and predict the quality characteristics of the fruits as affected by processing conditions. In this study, we found grinding conditions retard the changes in color and loss in phenolic compounds and antioxidant activity of ground apples. This new finding can be helpful for engineers and scientists to control and optimize the grinding system by retaining the high nutritional values of apple products.

Study the Effect or the Evaluate of the Addition of Ground Apple Powder as a Catalyst for the Bio-Enhancement of Natural Packed Carrot Juice.

Study the Effect or the Evaluate of the Addition of Ground Apple Powder as a Catalyst for the Bio-Enhancement of Natural Packed Carrot Juice.

First Report of Sclerotium Rot Caused by Sclerotium rolfsii on Yacón in South Korea.

Yacón, or ground apple (Smallanthus sonchifolius), is a perennial plant grown in the northern and central Andes from Colombia to northern Argentina for its crisp, sweet, and tuberous roots. In 2012, yacóns cultivated in the research field of the Gyeongsangnam-do Agriculture and Extension Services, Jinju, South Korea, suddenly died. The characteristic symptoms consisted of rotting, wilting, and blighting. Initial symptoms included water-soaked lesions on lower stem tissue near the soil line. Infected plants gradually withered, and white mycelial mats and sclerotia appeared on the surface of roots and stems at the soil line. The sclerotia were collected and disinfested by immersion in 1% sodium hypochlorite solution for 30 s and in sterilized distilled water for 1 min. Then, the sclerotia were placed on potato dextrose agar (PDA) and incubated at 30°C. Numerous globoid sclerotia were formed on PDA after 18 days of growth. The sclerotia (1 to 3 mm in diameter) were white at first and then gradually turned dark brown. Aerial mycelia usually formed many narrow hyphal strands 4 to 9 μm wide. The white mycelium formed a typical clamp connection after 5 days of growth. To fulfill Koch's postulates, 50-day-old healthy seedlings were transplanted individually into pots (10 × 10 × 9 cm) containing autoclaved soil. After 7 days, five seedlings were inoculated with colonized agar discs (6 mm in diameter) directly on the base of the plant, and five yacón seedlings were inoculated similarly with PDA discs as the control treatment. The inoculated and non-inoculated plants were incubated in a humid growth chamber at 28°C for 24 h and then maintained in a greenhouse. Eight days after inoculation, the yacón seedlings inoculated with the fungus died, whereas those treated with PDA discs were symptomless. The fungus was re-isolated from the artificially inoculated plants. To confirm the identity of the causal fungus, the complete internal transcribed spacer (ITS) rDNA region of the fungus was amplified using the primers ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') (2), and the PCR amplicons were cloned into the pGEM-T Easy vector. The resulting plasmid (pOR119) was sequenced in both directions with the primers M13F and M13R. The resulting 684 bp of ITS rDNA sequence was deposited in GenBank (Accession No. KJ944395). A DNA analysis revealed that it was 100% identical to Sclerotium rolfsii (HM355751). Cultures of S. rolfsii have been deposited with the Korean Agricultural Culture Collection (KACC 47750), National Academy of Agricultural Science, Suwon, South Korea. On the basis of symptoms, fungal colonies, the ITS sequence, and pathogenicity to the host, this fungus was identified as S. rolfsii Saccardo (1). This is the first report of sclerotium rot on yacón caused by S. rolfsii in South Korea.

Characteristics and Effects of Fructooligosaccharides in Yacon (Samallanthus sonchifolius)

Yacon [Samallanthus sonchifolius (Poepp. & Endl.) H. Robinson] , Peruvian ground apple, is a tuberous root crop with crisp, crunchy and sweet roots and considered as the king of oligosaccharides in Korea. Yacon’s fructooligosaccharides are non-digestible carbohydrates and composed of kestose, nystose, and fructofranosylnystose. The fructooligosaccharides have physiological prebiotic functionalities such the lactic acid bacteria of intestinal bifido bacteria growth, increasing mineral absorption, promoting formal functions, improving lipid metabolism, anti-obesity effects, and prevention of cardiovascular disease of triglyceride synthesis. The content of fructooligosaccharides in yacon was about 8.1% in fresh weight basis which was higher than those of other root crops such as garlic, budock, etc. However, during the storage period, the content of fructooligosaccharides decreased from 8.1% to 4.8% and 2.4% in 1 and 3 months after storage, respectively. Therefore improvement of storage conditions is needed to minimize the decrease of fructooligosaccharides. Considering these results and other studies on yacon’s biological functionalities, Various studies are needed to utilize the yacon as a functional food material.

Fruit‐based functional foods I: production of food‐grade apple fibre ingredients

SummaryWith the increased consumer interest in fibre‐enriched functional foods, industrial‐scale methods for functional fibre production are demanded. The development of a food‐grade fibre preparation method at lab scale that is feasible for industrial scale‐up is a pre‐requisite. This paper describes two lab‐scale fibre preparation methods that have potential to be scaled up to industrial setting for the production of fruit fibres containing desired bioactives and functionality. The two methods, one aqueous and the other ethanolic, were used to isolate fibres from Granny Smith apples (Malus domestica Borkh cv. ‘Granny Smith’). In the aqueous method, ground apple tissues were suspended in HEPES buffer (20 mM, pH 6.5), and then mechanically ruptured using an Ultra‐Turrax and ring grinder. Between steps, the cell‐wall materials were washed with the HEPES buffer. In the ethanolic method, ground apple tissues were stirred in 72% ethanol at 4 °C, filtered, re‐suspended in 72% ethanol and then washed. Microscopic examination and chemical analysis were performed on the resultant fibres. The aqueous method produced natural and uniform dietary fibres in the form of plant cell walls containing 0.282 g uronic acid per g dried fibre. By comparisons, the ethanolic method produced crude fibres containing only 0.182 g uronic acid per g dried fibre, the lower uronic acid content indicating the presence of impurities. Thus, the aqueous method appeared to be advantageous in terms of the retained pectic polysaccharide content and cost‐effectness for industrial scale‐up. Further characterisation using Folin‐Ciocalteu assay and high performance liquid chromatography indicates that the fibres obtained by the aqueous method contained significant amounts of phenolic compounds (2.6 mg catechin equivalent per g dried fibre). These results suggest that fibres obtained by the aqueous method may be more suitable for functional food applications where fibres with high pectic polysaccharide and beneficial phenolic antioxidants are preferred.