Audiences may be forgiven for falling asleep during Bach's "Goldberg Variations." The keyboard work was actually written as a soporific. A count, suffering from insomnia, asked Bach for a piece that his personal harpsichordist, Goldberg, could use to play him to sleep.

The result, an aria with 30 variations, is one of the most technically complex works in the canon. It might be regarded as the ultimate expression of Bach's genius and, using a theme he first composed for his wife, it is also deeply expressive.

The original is such a towering work, what to make of conductor/violinist Dmitry Sitkovetsky's orchestration for string orchestra, played by Minnesota Orchestra Thursday morning at Orchestra Hall? Might he just be gilding the lily? Not at all. He has created an arrangement that, while remaining true to Bach's sensibility, expanded the variety of textures and colors. A pizzicato variation was especially playful.

Many of the variations played like a traditional violin concerto, and Sitkovetsky created a brilliant solo part for himself. In many others he was just another member of the ensemble. As such, he sat himself at the head of the first violins, rather than in a position of greater prominence.

There were chamber variations that gave strenuous workouts to principal cello Anthony Ross, principal second violin Gina DiBello and principal viola Thomas Turner. They dazzled as much as Sitkovetsky -- no mean feat. He made his violin sing with profound emotion and prodigious technique.

The orchestra played with precision and pristine clarity, but also with a passion that was keenly affecting.

It might be sacrilegious to say, but Sitkovetsky's arrangement was more entertaining than the keyboard original. It certainly won't put anyone to sleep.

Sitkovetsky was less successful with the Mendelssohn "Italian" Symphony (No. 4 in A major, Op. 9) that opened the program. This is one of the most joyous symphonies in the repertoire, but rather than a sense of sparkling Italian gaiety, the opening Allegro vivace felt bloated and bombastic.

He was on firmer ground with the austere Andante, but the delicate minuet lacked grace. And the finale, a rollicking dance, was played with a drive that felt more Russian than Italian. It was all much less fun than it should have been.

William Randall Beard writes regularly about music.