Minimisation of vitamin losses in fortified cookies by response surface methodology and validation of the determination methods

Effect of different harvest times and processing methods on the vitamin content of Leymus

Objectives

The objective of this study was to investigate the effect of different harvest times and processing methods on the B vitamins and α-tocopherol contents of Leymus chinensis (Trin.).

Methods

L. chinensis was harvested on 11 July (T1 group), 16 July (T2 group), 21 July (T3 group), 26 July (T4 group), and 31 July (T5 group) in 2022 and processed using natural drying and silage fermentation to evaluate fermentation quality, chemical composition, in vitro digestibility and vitamin content.

Results

The fermentation quality of L. chinensis silage prepared at all five times of harvest was better. The silage fermentation group showed a significant increase (p < 0.05) in crude protein (CP), thiamin, riboflavin, pyridoxine and α-tocopherol content, a significant decrease (p < 0.05) in water-soluble carbohydrate (WSC) content, and small differences in neutral detergent fibre (NDF), acid detergent fibre (ADF), niacin and pantothenic acid content, when compared to the natural drying group. The content of thiamine, riboflavin, niacin, pantothenic acid and pyridoxine were higher in the pre-harvest period. In silage fermentation, the loss rate of thiamin, riboflavin and pyridoxine was positively correlated with pH and WSC, and the loss rate of thiamin and riboflavin was negatively correlated with lactic acid content. The loss rate of pantothenic acid was negatively correlated with pH and WSC, and positively correlated with lactic acid and ammonia nitrogen. The rate of α-tocopherol synthesis exceeded the rate of catabolism.

Conclusion

The content of CP, thiamine, riboflavin, niacin, pantothenic acid and pyridoxine were higher during the early harvest period. Silage fermentation preserved the chemical composition and vitamin content of L. chinensis better than natural drying and had no effect on in vitro digestibility. During silage fermentation, the acidic environment promoted the preservation of thiamin, riboflavin and pyridoxine, but promoted the breakdown of pantothenic acid, α-tocopherol content increased through synthesis.

Biological Properties of Vitamins of the B-Complex, Part 1: Vitamins B1, B2, B3, and B5

This review summarizes the current knowledge on essential vitamins B1, B2, B3, and B5. These B-complex vitamins must be taken from diet, with the exception of vitamin B3, that can also be synthetized from amino acid tryptophan. All of these vitamins are water soluble, which determines their main properties, namely: they are partly lost when food is washed or boiled since they migrate to the water; the requirement of membrane transporters for their permeation into the cells; and their safety since any excess is rapidly eliminated via the kidney. The therapeutic use of B-complex vitamins is mostly limited to hypovitaminoses or similar conditions, but, as they are generally very safe, they have also been examined in other pathological conditions. Nicotinic acid, a form of vitamin B3, is the only exception because it is a known hypolipidemic agent in gram doses. The article also sums up: (i) the current methods for detection of the vitamins of the B-complex in biological fluids; (ii) the food and other sources of these vitamins including the effect of common processing and storage methods on their content; and (iii) their physiological function.