Outer Husk Research Articles

Antifungal properties of quinoa ( Chenopodium quinoa Willd) alkali treated saponins against Botrytis cinerea

Quinoa ( Chenopodium quinoa Willd) is a Latin American food staple readily available in large quantities in Peru, Bolivia and Ecuador. The outer husk of the grain is removed prior to consumption to reduce its bitter taste. At present, quinoa husks are considered as a by-product with no commercial value, despite its high content of triterpenoid saponins (20–30%). Due to this, the present work was undertaken to test if quinoa saponins have antifungal properties against Botrytis cinerea and if this activity is enhanced after alkaline treatment, since recent reports indicate that alkaline treatment of quinoa saponins increase their biological activity. Six products were tested against B. cinerea: (1) non-purified quinoa extract, (2) purified quinoa extract, (3) alkali treated non-purified quinoa extract, (4) alkali treated purified quinoa extract, (5) non-purified quinoa extract treated with alkali but without thermal incubation and (6) purified quinoa extract treated with alkali but without thermal incubation. Untreated quinoa extracts showed minimum activity against mycelial growth of B. cinerea. Also, no effects were observed against conidial germination, even at 7 mg saponins/ml. However, when the saponin extracts were treated with alkali, mycelial growth and conidial germination were significantly inhibited. At doses of 5 mg saponins/ml, 100% of conidial germination inhibition was observed, even after 96 h of incubation. Fungal membrane integrity experiments based on the uptake of the fluorogenic dye SYTOX green showed that alkali treated saponins generate membrane disruption, while non-treated saponins had no effects. The higher antifungal activity of alkaline treated saponins is probably due to the formation of more hydrophobic saponin derivatives that may have a higher affinity with the sterols present in cell membranes.

Potential of Jamaican banana, coconut coir and bagasse fibres as composite materials

This paper presents an evaluation of the alternative use of three Jamaican natural cellulosic fibres for the design and manufacturing of composite materials. The natural cellulosic fibres under investigation were bagasse from sugar cane (saccharum officinarum), banana trunk from the banana plant (family Musacae, genus Musa X para disiaca L), and coconut coir 1 1 Coir – a stiff, coarse fibre from the outer husk of a coconut. from the coconut husk (family Palm, genus coco nucifera). Fibre samples were subjected to standardized characterization tests such as ash and carbon content, water absorption, moisture content, tensile strength, elemental analysis and chemical analysis. The banana fibre exhibited the highest ash, carbon and cellulose content, hardness and tensile strength, while coconut the highest lignin content.

Characterization of mango pit as raw material in the preparation of activated carbon for wastewater treatment

Utilization of wastes as adsorbents or as raw materials in the preparation of activated carbon for environmental applications is an interesting alternative to commercial activated carbon commonly used for pollutants removal. Physical and chemical characteristics of the raw material play an important role in the properties of the carbonized waste. In this work two components of mango pit (the outer husk: SEMAVE-H and the inner seed: SEMAVE-S) were studied. The materials without carbonization were characterized by ultimate and proximate analysis. Cellulose, hemicellulose and lignin were quantified by the Crampton–Maynard, neutral detergent fiber (NDF) and acid detergent fiber (ADF) methods. The thermal behavior was studied by thermogravimetry and adsorption isotherms of water vapor, methylene blue and nitrogen were measured. Optic microscopy, Boehm's titration and IR spectroscopy were also used. SEMAVE-H contained more cellulose (39.4%) than hemicellulose (15.6%) and the inverse was revealed in SEMAVE-S. The thermal behavior of SEMAVE-S was complex; four peaks appeared in the DTG curves being the more intensive at 234 and 348 °C. For the husk and the seed S sp ≤ 100 m 2 g −1 and the acid groups were the most abundant in both materials.

Development of a young coconut fruit trimming machine

A project was initiated to design, construct, test, and evaluate a prototype young coconut trimming machine. The purpose of the design was to trim most of the outer husk so that the coconut looked attractive and could easily be cut open. The prototype was based on the lathe cutting machine mechanism and was composed of a lathe machine with a body-trimming knife, a shoulder-trimming knife, a base cutting knife, and clamping mechanisms. In operation, the body knife first pared the midsection of the fruit. Following this, the shoulder-knife trimmed the top to form a conical shape, and finally the base cutting knife sliced the bottom of the fruit to form a flat underside. In this study, the key design parameters and their optimum settings were determined. The angle between the cutting edge of the body knife and the Y-axis perpendicular to the rotating axis of the fruit ( X-axis) was 76°; the angle between the cutting edge of the shoulder-knife and the X-axis was 56°; and the knife angle between the knife and the XY-plane was 61°. The rotating speed of the fruit – which was newly harvested – was 300 rpm. Based on these design parameters, a commercial prototype was manufactured and tested. This prototype has the capacity to trim 21 fruit/h, with the finished product on average containing 1.1% of untrimmed green area and 0.2% of fibrous area. The trimmed fruit were accepted by fruit traders and exporters.

Prediction of vulnerability of pear cultivars to bullfinch damage

The physical characteristics of the buds of 36 cultivars of pears were investigated in relation to susceptibility to attack by bullfinches. Measurements were made of bud length, basal diameter, median diameter, volume of soft central material, volume of outer husk (bud scales plus fibrous material) and an index of the effort needed to remove buds from the tree. Data were collected from pear cultivars, which had received either negligible or severe damage from bullfinches, and were examined using discriminant analysis. Using only two variables—bud length and the ratio of volume of centre to volume of husk—the discriminant function correctly classified 91% of the cultivars tested as favoured or non-favoured by bullfinches.

GERMINATION OF ACID-TREATED SAMPLES AS A MEANS OF ASSESSING MECHANICAL DAMAGE OF BARLEY

Studies on dried Proctor barley during a year of storage have confirmed a previous conclusion that germination after treatment with 50% (v/v) sulphuric acid was unaffected in undamaged samples but was reduced in those mechanically damaged. The treatment differentiated samples into groups corresponding to severity of harvest treatment, but removal of the outer husk and pericarp rendered corns more subject to mould attack. Use of acid of known specific gravity is suggested for comparative work.