Physicochemical, functional and emulsion properties of edible protein from avocado (Persea americana Mill.) oil processing by-products.

Avocado (Persea americana) is a tropical fruit that has drawn great interest its oil for foods and cosmetic industries; however, avocado oil processing by-product is a potential source of edible protein. Herein, edible protein was prepared from defatted avocado meal, and it's physicochemical, functional and emulsion properties were investigated. The avocado protein showed U-shaped exhibiting strong effect of pH, and a minimum solubility being observed at pH 4.5, confirming the isoelectric point of avocado protein. Nutritionally, the avocado protein contains all the essential amino acids. Avocado protein provided higher water and oil absorption capacities, higher radical scavenging capacity but lower in-vitro digestibility compared with soy protein. Furthermore, the avocado protein as emulsifier afforded a stability oil-in-water emulsion system, resulting in a greater emulsifying stability than that of soy protein. The present results highlight the potential source of edible protein from avocado oil processing by-products for functional food ingredients.

Comparison of physicochemical properties and in vitro digestibility of starches from seven banana cultivars in China.

Lots of bananas were wasted before commercialization. It is necessary to search potential industrial applications of banana. In the present study, starches from seven banana cultivars (labeled as A-G) were isolated and then characterized. These starches presented different and irregular shapes, such as sphere, long spheroid and polygonal granules. The distribution of size and analyses of average molecular weight showed more small granules in samples B, D, F and G than other samples. The amylose content varied from 22.59% to 38.40%. The crystal types of these starches were a mixture of B-type and C-type, and the relative crystallinity varied greatly. The differential scanning calorimetry (DSC) results showed that the onset temperature of gelatinization increased as follows: A < B < E < C ≈ D < F. The maximum viscosity of banana starch decreased as follows: G > C > D > F > E = B > A. The in vitro digestibility test showed that the content of resistant starch was very high in banana starches. These results would be useful to the application of those starches in food and nonfood industries.

The interaction of banana MADS-box protein MuMADS1 and ubiquitin-activating enzyme E-MuUBA in post-harvest banana fruit.

KEY MESSAGE : The interaction of MuMADS1 and MuUBA in banana was reported, which will help us to understand the mechanism of the MADS-box gene in regulating banana fruit development and ripening. The ubiquitin-activating enzyme E1 gene fragment MuUBA was obtained from banana (Musa acuminata L.AAA) fruit by the yeast two-hybrid method using the banana MADS-box gene MuMADS1 as bait and 2-day post-harvest banana fruit cDNA library as prey. MuMADS1 interacted with MuUBA. The interaction of MuMADS1 and MuUBA in vivo was further proved by bimolecular fluorescence complementation assay. Real-time quantitative PCR evaluation of MuMADS1 and MuUBA expression patterns in banana showed that they are highly expressed in the ovule 4 stage, but present in low levels in the stem, which suggests a simultaneously differential expression action exists for both MuMADS1 and MuUBA in different tissues and developmental fruits. MuMADS1 and MuUBA expression was highly stimulated by exogenous ethylene and suppressed by 1-methylcyclopropene. These results indicated that MuMADS1 and MuUBA were co-regulated by ethylene and might play an important role in post-harvest banana fruit ripening.

[Research progress on banana functional genomics involved in fruit quality].

Banana is one of the most important tropical fruits and main economical resource for tropical people. Banana quality is always becoming a focus for people to follow with interest. Here, we reviewed recent research progresses on isolation and identification of banana genes involved in fruit quality such as ripening, softening, glycometabolism, and scent, which will help us explore their functions and facilitate banana quality improvement.